Identifying and Tackling Fleece Imperfections

Let’s visit the topic of how to identify some imperfections and issues that you may come across while processing fleeces and some avenues we know about to tackle each one. Hopefully this removes some of the fear and uncertainty around fleece work by helping you be informed. This is developed for processors and shepherds alike and will be a constant work in progress as we come across new things and methods. This is a non-exhaustive list of causes and approaches and uses since we don’t know everything available. I will keep this updated accordingly when I am able. If you have any new puzzles or information to add, we would love to hear it! And for shepherds, we are always open to helping in fleece diagnosis for samples with the knowledge base we have.

Feel free to utilize this in conjunction with a checklist we have provided for you to take with you when skirting or shopping!


Cleanliness is a huge factor in fleece choice, but there’s no shame in dirty fleeces! They come off of animals living outdoors after all, and I’m a firm believer you can figure out how to work with any wool or find a use for it, though it might take some effort. It is mostly up to preference to decide how much vegetation you are willing to work with. As a heavy processor, I tend to work with really clean fleeces because the time saved not picking out vegetation is very valuable to me. However, I don’t really worry about dirt. Dirt will fall out as you process a fleece at every stage the vast majority of the time and will be a nonissue. I’ve even had Shetland from a farm with dirt pastures and uncoated sheep, and while it changed color significantly with a good wash, the dirt did not impede having a beautiful yarn afterwards. Do keep in mind that significant dirt content will affect your weight of fleece when washing is done. Primarily we are looking at the saturation of vegetation in a fleece when speaking about cleanliness.

Clean uncoated Jacob fleece with pointed tips next to coated Merino with blunted tips from coats

Coated fleeces are the easiest way to find wool that is virtually ready to be spun after a quick wash. The coats protect the fleece from debris and dirt, but do take significant effort to maintain. Sheep coats are typically made from rip-resistant nylons and need to be changed throughout the growth of a fleece, meaning shepherds need to have several sizes on hand. Too tight of a coat can restrict the sheep’s ability to regulate temperature and risk felting of the precious wool they are growing; too loose, and you risk injury to your animals or not enough wool protection. The tips of coated fleeces can be blunted and tender from consistently rubbing against the coats. Other risks include the sheep getting caught on things or deciding they want nothing to do with being coated at all. Additionally, coats can take a significant amount of time to maintain in terms of repairs and cleaning for the shepherd. Every shepherd has a reason behind choosing to coat or not to coat based on whether it works within their farm’s system. And with all that, I must applaud our shepherds for their work with them because they more often make our lives easier in the end.

That doesn’t mean uncoated wool is something to avoid. Some shepherds maintain immaculate care and can rival a coated fleece. Vegetation can be managed by proper bedding, a clean pasture and barn, and modified feeders and careful feeding arrangements. If you’re looking for wool that needs to be completely strong (say, for a weaving warp) through the entire fleece, uncoated adult wool should be void of the tender, blunted tips coats may cause. You would be hard-pressed to find longwool breeds with coats as well. Typically they do not use them as the coats can damage the lock formation and would need to be changed far too often. They can also be more prone to felting.

Fine vegetation in the left fleece is harder to get out than the large pieces in the right portion.

There’s most certainly nothing wrong with working through some vegetation. Large, loose pieces that are easily picked out are hardly a problem and VM, or vegetation matter, will fall out during every stage of processing, right down to the spinning. Your main concern is going to be coming across very finely broken up vegetation that is saturated in a fleece. This can be referred to as chaff, which is the husk around a seed, and those are the hardest pieces to remove. I’ve found fine hand combs to be the most helpful next to picking it out by hand. Flicking locks open prior to scour is another useful vegetation removal means. A good, hard shake can do a lot of good removing bits off of fleece.

Burr removal from dyed fleece

Burrs can be a real pain to come across as they are sharp and likely to disintegrate. The easiest way I’ve found to remove them is to isolate the locks affected, hold them over a trash can, and lift them gently up and off the spikes of the burr. With care, its possible to remove burrs intact and easily.

Drum carders will break the vegetation down further and embed it more. They are not a means of removal. Hand combing an entire fleece or hand picking vegetation out can be a huge time-consuming undertaking, so this is where the preference part comes in and you will need to determine how much time you want to spend with a particular fleece before you have spinnable wool. It is a little hard to quantify what is “too much” in vegetation since it is dependent on preference, but anything above roughly 10% saturation of an area, I tend to skirt out. I would still consider even 5% of an area to be moderate vegetation as well. And again, that is purely preference as I prefer to work with cleaner wools to save time. I am not yet familiar with the vegetation removal that hand carding can handle, but will update this section when I am.

Wool tumblers I have not found to remove much vegetation from fleeces with lanolin in them. It does a pretty great job on Alpaca and Llama fibers, though! I find a wool tumbler paired with some type of blower, like a leaf blower, most useful for dust that may come from Alpaca and Llama. These animals participate in dust bathing to aid keeping themselves parasite free, so their fleece ends up quite dusty.

Here you can see our tumbler with Llama fiber. The dust below was blown out with a leaf blower while the motor rotated the tumbler. The resulting debris is then swept up and disposed of as this animal does not reside in our climate and we do our best to avoid distribution of seeds from invasive species. Below, you can see that the vegetation wasn’t quite removed.

The video series No Fleece Left Behind and this one from The Natural Spinner do an excellent job discussing methods to stretch your wool use no matter the condition.

When it comes to manure tags, I prefer to take any and all off a fleece no matter how aggressive that may seem. I haven’t found a way that efficiently removes or cleans them off fiber and in long term storage, they will be a quick producer of mold or cause the fleece to “sweat” inside of a bag as they decompose. They are easy to find as a clumpy, black, and tar-like substance caught in the raw fiber. Sometimes this can be confused with sap, but sap is just as frustrating and should be skirted off as well.

You might also come across bugs in fleece. Don’t always be alarmed. Sometimes things get caught up in the wool and die. It helps to be familiar with what species to look for that are wool-eaters, such as Clothes Moths and Carpet Beetles, and what are not. I’ve come across many a wasp or harmless beetle from pastures. It’s a common side effect of being a fiber from outdoors.

In addition, there could be bodily contaminants from the sheep themselves. Shown above is a scab from a scratch that is still attached to the bottom of the wool. I have only ever come across this single one in all of the many fleeces I have worked with. A large prevalence can indicate a skin issue such as Lumpy Wool (see below), but this instance is not that case. I simply trimmed the contaminant off the bottom of the locks and continued with my work. I’ve also come across hoof clippings since sheep typically have their feet trimmed at shearing time and they were most certainly missed in skirting, but don’t be surprised if you spot one on occasion!

A Couple of Fleece Characteristics

Open Fleece vs. Crossing Fibers

The distinction between an open fleece and one with crossing fibers is very good to know as it can be an imperfection in some breeds, though it is a characteristic and not an imperfection in and of itself. It is not something that will hinder processing. Open fleeces typically occur in longwools or sheep developed on wet lands where the sheep need the ability to shake the water away from their skin. This means you have very distinct and separate locks and could part the fleece down to the skin with ease. Breeds like the Romney that have now moved to America are starting to develop crossing fibers in their fleeces through breeding and cross breeding often enough to change the breed standard. They are not meant to have them since the Romney was developed on marshlands and intended to have an open fleece. This is one example of breed standards changing by region or organization.

Sheep with fine and dense fleeces like Merino and Romeldale will have more crossing fibers that attach locks together in a crisscrossing manner and insulate the animal and protect it from having wetness and dirt penetrate to the skin. Sometimes you can see just how dense a fleece has lain on an animal by the distinct line of dirt in the locks.


Again, dual-coated fleeces are another characteristic and not an imperfection unless it is showing up in breeds that are not meant to have them. The Icelandic shown above demonstrates a full lock next to its tog (outer coat) and several lengths of thel (under coat) that can be separated from the single lock. Typically in sheep wool, the outer coat is the coarser of the two. These fleeces are only challenging in the sense that they have so many options to go with. You can work with these with both coats intact or separate them and get multiple types of yarn from a single fleece. This does add time to processing, but can be really fun. If you are seeking to blend them together, be sure to thoroughly blend with more passes over your tools than your average fleece.

Type B Pygora Fleece with short Guard Hairs removed

In Pygora goats, a cross between a Pygmy Goat and an Angora Goat, there are multiple fleece types. A Type A fleece has an average staple of 6″ and more closely resembles Angora fiber. Type B averages 3-6″ and is a pretty decent blend of the two and has a feeling of cashmere. Type C is the softest yet with an average of 1-3″ and very similar to cashmere. The interesting part of these fleeces is the under coat is the coarser of the two fibers in the dual-coat and is short and hairlike. This fiber needs to go through a dehairing process by combing the short fibers from the bottom of the lock before being spun.

Finding Crimp or Curl Per Inch

Crimp is what gives fleece its ability to have memory and elasticity. It also can assist in giving the fibers more “grip” to each other while spinning. Beyond memory and elasticity, crimp will not line up once spun and this captures air between the fibers to create further insulation. Not all breeds produce crimp or curl, so this is another characteristic to take into account when seeking appropriate expressions of a breed. Fine wools typically have more crimp or curl than coarser wools, which helps to insulate the animals. Higher crimp means more elasticity. Crimp is a highly heritable trait in fiber animals as well, so selecting for animals with crimp matching with a breed standard range is important. Research with sheep has also shown that a good crimp pattern indicates properly arranged follicles under the skin as well.

Above we have two fleece examples for finding crimp per inch. On the left is a Corriedale lamb who sports 9 crimps per inch when held next to the ruler. You can count each bump visible in a lock. You can count curls in this same way. She has Consistent Crimp so you can see 9 through every section of the lock. If it was Inconsistent, you would find a different count at different lengths of the fiber. The Romney Cross on the right has 5 crimps per inch and is also consistent. The crimp on both fleeces is what we would consider Organized Crimp, meaning it is very defined and together.

This Shetland fleece on the other hand, shows Disorganized Crimp. You can not see an easily determined stack of bumps in the lock formation. You can still count these, but may need to take extra care with just a couple fibers instead of the full lock. Different areas of fleece will show different ranges of crimp as well. Pine Knoll talks wonderfully about the changes in crimp as sheep age or are exposed to different conditions here. There is also an interesting study here about crimp in Alpaca.

It is possible to play around with something called spinning to the crimp count. This means spinning a yarn that has just as many twists per inch as there are crimps or curls in a fleece. Theoretically, your yarn will be more inclined to balance and being an easier knitting product, but this isn’t a steadfast rule and there’s lots of applications where you wouldn’t necessarily want this to be the case, but it is a fun tool to play with!

Fleece Imperfections

Staple Length Variability

Staple length is the length of a given fiber in a fleece. It is a good practice to audit different areas of a fleece as the locks can grow in many lengths across an animal. Breeding practices often put an emphasis on fleece consistency, meaning the entire animal grows the same length of fiber. Quilting is a term used when fibers are different lengths for different colors of fleece like on spotted sheep that gives it a quilted appearance from the cut side and is a disqualifier in breed standards. There may also be different types of fibers within a fleece based on location. We will get to what Kemp and Medullated fibers are below, but a fleece can be broken down into sections as well. The neck is typically the most fine wool and also quite dirty and usually skirted out. The back line can sometimes be skirted out for being dirty, but also consists of fine fleece. The sides of a sheep will fall somewhere in the middle and typically make up most of your fibers. There is coarser fiber at the legs and belly of a fleece and you may find these fibers at the edges, but they are also skirted out at shearing time by the shearer. Below is a useful diagram of what a fleece will typically look like intact. All of the area in color is often skirted off since they are not the prime fibers. A fleece is easiest skirted cut side down on a wide mesh or bar table so that second cuts fall through to the floor with a good shake. After skirting, the sides would be folded inwards towards the center and the rear of the fleece is rolled towards the neck. The shoulder is utilized to tuck into the roll and hold it intact.

With all these different areas and types of fibers, there may be difference in length among them. You measure a staple length by laying a lock unstretched next to a ruler. You can also do the thumb trick by capturing the cut end of the lock between your thumb and finger and then bending the lock up over your thumb. Your thumb is about 3″ and will give you a rough estimate of spinnability. 2.5″-3″ is about the minimum length for ease of spinning and you typically want most of your fibers to fall at or above this range. Anything less will increase difficulty, but is not impossible. If you do come across a fleece with inconsistent length, it will either do well carded or with sorting the locks by length prior to scour. Sorting locks will assist combed fibers in drafting very smoothly by all being the same length in a given portion.

Kemp and Medullated Fibers

Kemp fibers, shown above, are hairs in a fleece which are not constructed like wool fibers. Many breeds grow kemp fibers though there are breed standard restrictions as to how many a sheep may have in most cases. These are pretty easy to pick or comb out if they are not too saturated in the fiber. The fibers above are very stiff and thick. They differ plenty from the Jacob fleece they inhabit and are easy to spot.

Coarse wool fibers, Medullated Fibers, and Kemp from the same fleece

Medullated fibers are the ones that fall somewhere between a kemp hair fiber and a wool fiber. Typically longer and sometimes with a curl to them, they resemble our own hair. They are also easily picked or combed out, though some fleeces can be quite saturated with them like the one above. Both fibers will make your projects coarse if left in. If you are coming across quite a lot of medullated fibers, perhaps consider using this wool for upholstery, rugs, or home goods.


A break in a fleece is when you are able to pull on the locks and they quite literally break apart. They can be caused by any stress a sheep can endure, be it lambing, significant weather, a change in home or diet, or illness. At the time that stress occurs, the fleece will weaken as the sheep’s body allocates its resources away from growing fiber and into caring for the animal. Tenderness can also occur which will make a fleece feel brittle and is sometimes described as being “tippy” if occurring at the tips. To determine a break, grip each end of a lock and tug apart. You can do this near your ear and hear the brittle fibers separating as well and is best described as sounding “crunchy.” There is also a snap or ping test so that if you snap a lock quickly, you can hear it sing like a high drum if it is strong. I don’t find the ping test to be the most reliable and would rather take a lock and tug on it and put it under stress to test it. You can feel locks separating or sounding crunchy if they are not strong enough. Breaks can occur in just parts of a fleece and not its entirety, so it is best to audit multiple areas.

If a break or tenderness is, say, across the middle of a 3″ lock, you would end up with 1.5″ of spinnable fiber on either side which would be difficult to work with. If a break is closer to either end of a longer lock, then you can snip it off or complete the breaks by pulling the fiber apart and continue with the spinnable fiber. Do note that when you take what would be a pointed and tapered fiber and then cut that pointed and tapered end off, it will become a blunt fiber and may add coarseness to your yarns. I generally prefer manually breaking them off to cutting. Sun-bleached or weathered tips on a fleece can develop breaks or tenderness, but some can also remain quite strong. Lambs often have tender tips to their fleeces from their first newborn wool. It can be called “tipping” a fleece if a shepherd has shorn these delicate lamb tips off of a lamb fleece.

Tenderness can also be worked with. If a fleece feels weak, but does not break, it is reasonable to still process it intact with hand tools that are more gentle than mechanical ones. Keep in mind the yarn resulting from a tender fleece will not withstand the same amount of abrasion, tension, and abuse that a properly strong wool can endure and your projects should be planned accordingly. This is something you can learn over time what a strong vs. weak fleece feels like and is hard to quantify over text.

Shetland Rise

This is a good moment to note the Rise in a Shetland’s fleece, or any sheep that still retains the ability to shed its wool naturally, called Rooing. A Rooed fleece can be some of the softest fibers as both ends of the fleece will be pointed and tapered fibers. However, since the rise is the point where a fleece has begun to separate and break off from the fibers coming in for the next growth, they are tender or a break. Shepherds will do their best to catch a fleece for shearing before rooing begins as that can produce the strongest fibers. A properly rooed fleece will not have the rise attached to it, but it is not at all difficult to remove. Similar to breaking off a fleece at a break.

Sun-bleached Tips

Sun-bleached tips

As mentioned above, sun-bleached tips on a fleece can develop breaks or tenderness, but some can also remain quite strong and its entirely dependent on the fleece. This normal weathering can also occur despite coating. Some breeds, like Gotland, tout UV-resistance that helps them resist such fading and weathering. Fleece with sun-bleaching should be tested for strength in various areas as usual.

The coloration will give a warmth to your projects if left in. The silver area of this Romeldale fleece shows just how much alteration you can get during blending from a prevalence of sun-bleaching.

It is possible to snip the tips off if they are rather short. This Black area of a Jacob fleece shows some warmth and browning in the left from the tips being left on. In the right sample, they have been snipped off and the color is much more uniform. Do be aware that trimming tips bluntly can cause some coarseness in a project.

Second Cuts and Shorn Locks

Second cuts or shorn locks are something that occurs at shearing. A shearer tries to take a fleece off in one pass, as each pass of the clippers will create second cuts that are very tiny clumps of fibers that are cut short. These can create nepps or lumps in your processing and it is best to remove them prior unless you are deliberately going for a chunky and bumpy art yarn. I have spun some fleeces with purposeful use of second cuts for texture. Most are shaken out at skirting and shearing. They are pretty easy to find if you take the cut end of the fleece and make a gentle pinching motion across the fibers, the second cuts will come right up. A good, hard shake can be excessively useful in removing second cuts as well. Shorn locks can be a bit more of a problem if the clippers have gone through the middle of the fleece as you have then lost your spinnable length. If you are dealing with shorn locks, the very short fibers may just be an excellent candidate for felting purposes. Think dryer balls and felted soaps for simple projects.

Second Cuts being utilized for purposeful texture.

Felting/Cotting and Compacted Fibers

Felting or Cotting is when a fleece has matted together prior to shearing. This can happen when, among other causes, coats are too tight and rubbing, when the animal has lain on the area and frequently given it abrasion, shearing has waited too long, or it has just formed around debris. Wool is covered in microscopic scales that act as a ventilation system that open when hot and close when cold. When the scales intermesh, they can essentially become bonded and these fibers are unable to be separated and cause issues with processing. These areas should be skirted out, but if it is occurring at the very base of a lock in a very thin amount and otherwise they are easy to separate the rest of the length, it can be trimmed off. Felted or cotted fleeces or portions of fleece are not a total loss if you come across it and can make excellent candidates for felting cushions or rugs! With a Merino that showed some felting, I was able to pull the fibers into a thick roving and spin a very, very fat textured yarn as well.

Lightly felted Merino pulled into roving by hand and spun.

Compacting of fibers is a step towards felting in which they become tight and hard to separate, but not impossible. This might be eased by steaming the fiber to open the microscopic scales back up. Carding compacted fibers can also aid brushing it back open. These options also work for compacted dyed Top.


Banding in a fleece is what happens when the color of a fleece changes abruptly during fiber growth. It looks like horizontal striping on the locks. Other mammals carry genetic markers to develop these changes along their fur growth, such as Agouti colorations, but not so with sheep. There are three possible causes for banding. One being a seemingly inherited trait for color to stutter in certain areas of a fleece and seems to be primarily a Romeldale trait. The other two causes are types of copper deficiencies. Sheep ride a fine line between having too much or not enough copper and are susceptible to copper poisoning as they have a greater difficulty disposing of excess copper minerals in their systems. It is still a necessary mineral for their ability to function, though.

Fleece is primarily pigmented by Pheomelanin, spherical grains of pigment, and Eumelanin, ellipsoidal organelles of pigment. Eumelanin occurs most often to develop a range of black to brown pigments and Pheomelanin occurs in red to yellow shades. If a sheep does not receive enough copper, Eumelanin stops being produced and a fleece may turn white and have a possibility for weakness, though it does not always cause structural damage. The other possible avenue with copper deficiencies is the presence of too high of minerals like iron or zinc that can interrupt the ability for the animal to use the copper it intakes. You can read further in depth on this at Pine Knoll Sheep and Wool who does an excellent job explaining it.

We will be adding or own photo to this section when a sample can be acquired.

Yolk and Canary Stain

Canary staining plagues me a bit. There seems to be no solid information to its cause or what you can do with it. The lock on the left in the photo above has a gentle yellowing from lanolin or bacterial staining from long term storage. This is a very soft ivory and is normal to come across in white fleece, even freshly shorn. We call this a Yolk, or the combination of lanolin and suint (sweat), staining. We recommend washing your white fleeces quickly if you can. Often, in industrial settings, a fleece is exposed to a very controlled oxidative chemical solution for a very controlled amount of time to bleach it white without incurring strength damages. It is not something I would ever try in a home setting as we do not have the means of such control. Above, the lock on the right shows canary staining which is a vibrant and bright yellow that will not wash or even bleach out. Canary staining has been said to be caused by illness, bacterial reactions with sweat in a fleece, fungal infections, or even that it is hereditary and the treatment is to cull the animals which is not a theory I believe. It’s been said that it can develop if a white fleece is left in the grease for storage as well and I would agree with that as a progression of Yolk Staining turning into Canary Stain.

Truly, it seems as though canary stain is just a symptom of many different things. This particular fleece we determined may have been stained from bacterial interaction with a sweaty sheep that was coated in a humid climate. There is some disagreement if canary staining causes damage to a fleece or not. Also if it will take dye or not. In this particular instance, this fleece was washed immediately and did not sustain damage. It remained strong after over 6 months of sitting. If you had a sheep with an illness that developed it, then I could definitely see where a break or damage may appear to be caused by the staining. As for dye, perhaps that is dependent on how the staining came about. For this fleece, it takes dye fantastically and makes for a beautiful fiber. With this information, canary staining can potentially be worked with, but it could be a signifier of further issues and should be approached with caution and the shepherd informed if it is found soon after purchase and not a result of storage. Below, you can see the color augmentation canary staining can bring about. It’s perfectly within reason to work directly with a canary stained fleece and embrace the hue as well.


Scurf is one of the awful things to come across in fleece and can really hide in it. It is caused by skin mites and your shepherd needs to know about it as soon as possible. Dandruff is not the same as scurf and will appear as small flakes that fall easily out of a fleece with little to moderate effort. Below is a photo of dandruff in a fleece before and after a light teasing to the ends of the locks. You can see it removes easily and is not to be confused with the Scurf above that will not separate. Angora goats in particular can be prone to dandruff and it can be normal in sheep dependent on their climate or growth conditions, though not desired.

Scurf can be characterized by large and small irregularly shaped flakes, sometimes yellow in nature and sometimes described as gummy or sticky, at the cut end of a lock. They will not come out with virtually any method of removal. I have found that in a fleece with light scurf like the black fleece above, you can take a pet flea comb to the ends and remove some of the scurf. It’s not foolproof, but it definitely removes a portion of it. You can also just trim the scurf ends off a fleece if it is long enough. We have also found that affected fleeces can be repurposed into cushions or rugs by felting wool onto the bottom of the fleece. So if you do come across it, it’s not necessarily a total loss. You may just have to get creative with some options. Scurf may also indicate further issues in a fleece and should of course be entirely avoided if possible.


Mold is a fleece killer. This is the one thing I have never been able to bring a fleece back from. There have been suggestions to wash with things like lemon juice added in to kill the mold or mildew smells in portions of the fleece that are not directly affected by the mold growth. This is not something that has worked for us. It will also eat through your fiber and weaken it. The two times I have come across mold was from a fleece stored in the grease for an extended period of time in tightly tied plastic bags, which is really not recommended, and another that was also stored in plastic in very hot and humid weather on the way to a show for a few weeks. I would bet on it developing in a fleece stored with excessive manure tags that is let to sweat inside of a plastic bag as well. Best suggestion to avoid this is make sure you have checked the locks throughout a fleece bag, particularly the middle if you can, and to wash your fleeces soon after arrival and transfer them to cotton bags for appropriate storage. If you need to store long term, it is ideal to store a fleece very dried out and may be beneficial to lay a fleece flat for a few days to dry out before any time it will be storing long term in an open plastic bag.

We love using old pillowcases, old t-shirts with the neck and arm holes sewn up, or our 24″x36″ cotton drawstring laundry bags. This gives the fleece a safe breathability for its storage. If it must be stored in plastic bags, it is best to leave them untied and open to introduce air to the fleece.

Breeding Crayon

Some shepherds use Marking Harnesses attached to their rams with something like a crayon on the front of it. It helps to signify when a ewe has been covered by that ram and her odds of being expecting and at what dates. Often, multiple colors are used for different date periods as well to further narrow it down. Typically any affected fiber is skirted away from a fleece, but you may come across some that is not. I’ve heard some may wash out entirely, but that may be dependent on what products were used to mark the sheep and what your cleaning materials are capable of removing. It doesn’t hurt to try! In the fleece sample above, it washed out very easily! Additional information in this Wool Contamination from Applied Agents PDF.

Fleece Rot

Fleece Rot is not something we have personally encountered in fleece, but have read on. Likely fleeces with this will not make it to sales. It is a superficial bacterial infection caused by prolonged wetness exposure, typical of heavy rainfall. Skin lesions develop and excrete a bacteria called Pseudomonas aeruginos. This does not need treatment and may self-resolve, but it does lead to an increased risk of flystrike and that will need treatment. Fleece may become matted in lines and develop permanent distinct bands of discoloration in yellow, brown, orange, violet, green, or grey. This is not to be confused with Canary Staining. It does not wash out. Prevention is handled by selecting for animals with resistance to it and shearing before heavy rainfall seasons as shorter fleece will dry faster. See this PDF, this PDF, and this PDF for more.

Lumpy Wool

Lumpy Wool, sometimes known as Rain Scald, is another bacterial infection from Dermatophilus congolensis. Fleeces affected will not make it to sales. This condition causes hard scabs to form on the skin that then attached to the fleece and lift with it as it grows. It primarily forms in wet conditions and is transferred between animals by contact. It will result in loss of body condition and death and is much more serious than Fleece Rot. It also increases risk of flystrike. More about Lumpy Wool available in this PDF and this PDF.

Troubleshooting Stains

Grass-stained locks – Photo provided and used with permission from anonymous shepherd

A contact of ours was speaking with a shepherd about some odd staining they discovered in their sheep’s wool. The suspicion was that since their rams spend a good amount of time resting each other’s heads on the other’s back, that they may have drooled chewed cud into the fleece and caused grass staining. However, as spoken of above, green staining can also be indicative of bacterial causes. It is especially suspect that the staining is at the bottom of the locks. Bacterial stains like Fleece Rot and Canary Stain will not lighten or go away with any manner of wash. Commercial operations bleach out Yolk Staining and other contaminants with oxidative chemical solutions under controlled measures as it can risk the integrity of the wool. Bacterial stains are considered disqualifications for processing white wools and can ruin a bale because they do not respond even to this bleaching method. When you need to figure out if staining is bacterial or other in nature, you can expose a lock to Hydrogen Peroxide and water to see if it lightens or removes it. The peroxide does put that lock at risk of losing strength and breaking down, but it will give you an answer as to a cause.

The staining noted on the locks above did lighten in a peroxide exposure test. The shepherd did further testing and was able to soak the locks overnight in a water and Dawn Dish Soap bath and then scour as normal the next day. The staining became very pale green afterwards. It is unclear if the Dawn was wool safe or an enzymatic version of the soap that would degrade wool. When washing fleece, you do not want to use soaps with enzymes geared at breaking down proteins as wool is a protein itself. It is also noted that after shearing, the sheep showed staining on the wool left on them that was washed clean by the rain, further reinforcing the idea that this was not a bacterial stain.

Rubber Lining of a Coat Shed Into Fleece

We had an instance where a shepherd reached out for us to assist with her fleece coats shedding a thin rubber lining throughout some of her fleeces. This is not to be confused with scurf or dandruff and was distributed heavily in the tip side of the fleece. This was a really great opportunity to figure out a problem together and talk about troubleshooting fleece issues.

On arrival, we took about an ounce of fiber and divided it up into various testing portions, leaving some raw fiber to reference back to. These portions were laid out for flicking before and after wash, combing, and hand carding. The goal was to approach the fibers with each mode of processing we had available to us and keeping in mind techniques used to remove very fine vegetation.

Utilizing hand combs and hand carders that are at our disposal, we were able to figure out that hand carding embedded the rubber shed more firmly into the wool while combing started to get us on a correct direction. The primary issue was that once the lanolin was removed from the fleece, it was acting as a netting to trap the rubber in the fibers. If we were able to thin it out off of our tools and blow on the combed or flicked fibers, much of the rubber flung out. We did lose some in the wash as well, so combining the knowledge of that and the net-like behavior, the next trick was to try flicking the locks open prior to wash. It worked rather well! This is something that can work nicely for fine vegetation as well, but vegetation tends to have more grip to it than this rubber coat lining did.

Flicking the locks open before wash and then combing after was our best bet. We saw a huge amount of removal and the few specks that remained flung out very easily during spinning. This proved to be not much more effort than sorting locks for washing would take and that kept time investment lower as well, which is another goal when troubleshooting and hoping for the best methods. This is also how I will be approaching the fleece above that has dandruff trapped in its lock ends. Overall, we’re very pleased with the results of the final tests as the wool came completely clean by the time it was yarn and we were able to save the shepherd’s fleeces for sales and figure out an approach for this issue for anyone else that may encounter it. It never hurts to take the time to troubleshoot a fleece with various processing methods available to you. Every imperfection is a learning opportunity and you can’t go wrong learning something new.

Fleece Cards and Packing

I wanted to add on a couple quick resources here as well for those selling fleece. Fleece cards are really important to send out with your fleeces. These should be clearly written with some simple and necessary information laid out. This helps your buyers keep track of fleeces in their stashes and acts as a nice way to get ahold of you for more in the future. I really love a good fleece card and my favorite ones tend to contain Farm and Contact Info, Sheep, Breed, Staple Length, Year Shorn, Weight, Micron or Comfort Factor if the fleece was tested, and some general observations of the fleece characteristics in a Notes Section.

Also the easiest format to use when shipping raw wool is vacuum packing. Darkside Shearing has a wonderful video available here. We’ve utilized this ourselves and it is really space and shipping cost saving. It is also just plain fun to do!

We hope all of this information is really helpful for fleece workers and shepherds alike. We are including a simple checklist document to accompany this. Take it along when skirting or when looking at fleeces to purchase and mark off which things you’ve checked a fleece over for to help keep track!

Do check out our other Wool Processing posts or our Scour Method as well!

Percentage Based Scour Method by Fossil Fibers and LongDrawJames

Now that we have spoken in depth about common scouring agents and methods by which they can be tested, we can present our method! We are very excited to share this with you. This method is based on using a percentage of scour to raw wool weight to strip the layers of contaminants off of the fleece. After testing the scours at 3% of their weight, we knew we wanted a little more power at the beginning of the wash process. This method uses 2 baths at 5% to do the bulk of the cleaning and then 3% until your water achieves a correct transparency that denotes the lanolin to be removed. This method does work with any setup preference you may have, be it baskets, bags, or washing loose in the water. Your main factors here will be soap choice, water temperature, water volume, and being able to monitor the appearance of your water. We have done extensive testing with the help of several other wool workers and many of our own fleeces over the past few months.

For myself, I use large sports laundry bags with an open mesh to wash a pound at a time in 3 gallon tubs and the slotted spoon shown to push the wool into the water so that it is submerged in the new bath. If I am doing something like sorted locks of a fine wool fleece destined for combing, I will put them in small lingerie washing bags or stacking mesh baskets that allow them to lay flat and contained instead of my large mesh bags. In between baths, I gently squeeze some of the excess water out so that less carries over into the new bath. You really do not want to squeeze too much or too hard so as not to cause felting. No other manipulation of the wool is done in my process and I have not come across felting problems in any grade of fleece. We are letting the soap and water do all of the work here. The photos below are all taken after this gentle squeeze.

Bath Progression from Cold Soak and Scour Baths 1-7

You can clearly see in photo one the dirt removal done by cold soaking a fleece. Again, we found this to only be a necessary step in fleece that is quite saturated with dirt and this can be skipped based on your own preferences. For baths 1 and 2, there is a strong opaque milky look to the water. This is something you really want to see in your scour baths as that appearance is the lanolin leaving the fleece and staying behind in your water. As the baths continue, the water regains its transparency and becomes quite comparable to the look of the water with soap only. I generally find 5-6 total scour baths using Unicorn Power Scour and then 2-3 rinses will be sufficient for most breeds. By now, I’ve learned to easily tell when I’m close to the end of my scour baths based on water appearance.

Soap Only, First Scour, Last Scour

It is really important to keep note of what this soap only look is for your wool wash to determine when is best to stop. It is entirely possible to damage, or “fry,” your fleece with excessive soap use. The clouding left in our last scour is not milky or opaque in appearance, but simply leftover dirt. I worry less about dirt leftover since it will fall out in all stages of processing, but you can continue to rinse your fleece after soap use is over to remove more dirt. This method of watching your water helps you respond to your individual fleece and use only the soap required to reach the results you want. Some may harbor more lanolin than others. Camelids do not harbor lanolin in their fibers, so a more mild approach can be taken for them. They could use a less powerful soap and less scour baths to achieve desired results. For instance, knowing from our test results that Kookaburra did not remove lanolin as we desired, but still removed dirt in an acceptable manner, our leftover Kookaburra will likely be our choice for washing our Camelids. Do note, higher temperatures can still help certain soap formulations perform at their best for cleaning these fibers. The method detailed below primarily pertains to sheep’s wool and oily goat’s fibers, such as Mohair. Knowing how to scour your own wool to desired results can be useful not just in your own processing, but in preparing your fibers for milling as well. Small mills typically charge a wash rate since it takes a significant amount of time to do so, and this can save you some cost there as well.

I’ve also found that in a small home operation, 1 pound per tub is a really manageable size. On fleeces with lighter lanolin content, I have gone up to 1.5lb per 3 gallon tub without error, but I wouldn’t do much more than this at a time. This keeps my water tubs light enough to carry easily and makes the amount of water needed to reach desired temperature is manageable as well. To reach temperature, my own tap water does not go much more above 120F, so I alter my water with 3 pots of water brought to a near boil on my stove. The number of which was determined by use of a thermometer and practice.

A spin dryer can be of assistance in reducing drying times at the end of washing. Truly, we use ours all of the time for everything from wet handspun to our fleeces. If using bags to wash, you can toss the full bag in the spin dryer, or unload it depending on preference. After running the fleece through the spin dryer, we lay it out flat in a well-ventilated room on an accordion rack that has window screens on it. This setup works for us, as we can collapse it and store it flat elsewhere until needed. Cotton bags make an excellent long term storage for washed fleece to give them breathability. You can even use old t-shirts with the arms and neck sewn up or old pillowcases. Improper wash or storage can lead to discoloration of your fleeces, particularly those that are white.

Our hope is that this eases any fears about learning to scour wool and helps improve the skills of others that already do. This method development was a long process that taught us so much about how our scour formulas work with our fleeces and water. I’m so happy we joined forces with James and were able to improve the end results of our washes. Since we sell washed fleece, this has helped us produce the best expression of every fleece we offer. The ability to customize our washes to each project and fleece was sorely needed! I knew there had to be a way that was not a strict blanket-coverage answer.

Special thanks to James Perry (LongDrawJames) whose assistance writing and in deciphering these scours was invaluable. And to our method testers Felecia Marottoli (one.wip.wonder) and Alissa Kuehl (foxysfiberwares). Your contributions and input have been so appreciated.

Scour Tools

Percentage Based Scour Method in Lab Protocol Format

Materials & Reagents:

2 plastic, or other material capable of withstanding high heat, tubs with enough room to hold a volume of water that is at least 3 gallons


Thermometer (a simple meat thermometer will do)

Measuring spoons

Dishwashing gloves

Scour of choice

Screen or mesh material for drying

Optional: Serving spoon for gently manipulating wool in hot water

Optional: Pans to heat water to specified temperatures

Optional: Mesh laundry bags or baskets to hold the wool with sufficient space for the wool to lie mostly flat

Optional: Spin dryer or fan. Spin dryer will greatly reduce dry times.


Day 1 if implementing a cold soak method

  1. Weigh your raw fleece.

Note: This will be important for determining how much scour to use.

  • Fill one tub with cold water.
  • Carefully place fleece into the mesh bags or basket and submerge in cold water overnight.

Day 2

  • Scours 1:
    • Fill the next tub with a volume of hot water (130-140 °F/55-60 °C) that is at least 3 gallons per pound of wool to be washed.Add 5% scour (based on the weight of your wool – See Table 1) to the hot water and mix with serving spoon. Alternatively, you can add the scour first and pour the hot water in second and allow the water to mix it as it fills.Carefully lift fleece out of its current tub and very gently squeeze out some excess
    • water without over-agitating the fleece. You may want to skip this for some fine wools. Be incredibly careful not to burn yourself!
    • Submerge fleece in the scour bath you just prepared for 10-12 minutes.

Note: Lanolin dissolves at temperatures above 120 °F/50 °C. Make sure your water temperature does not drop below this value. Your tap water may not reach desired temperatures, use pans heated on a stove to alter the water to the correct temperature.

Note: You may alter measurements from Table 1 into standard measurements by rounding up. i.e. 5% scour to 16oz of wool is 1.6tbsp. You may use 2tbsp in this easier.

IMPORTANT: It is important to keep the temperature consistent once your wool is in hot water as wild temperature swings from hot to cold will cause your wool to felt.

  • Repeat steps for Scour 1 once to complete Scour 2.
  • Scours 3+:
    • Fill the next tub with a volume of hot water (130-140 °F/55-60 °C) that is at least 3 gallons per pound of wool to be washed. Add 3% scour (based on the weight of your wool – See Table 1) to the hot water and mix with serving spoon. Alternatively, you can add the scour first and pour the hot water in second and allow the water to mix it as it fills.Carefully lift fleece out of its current tub and very gently squeeze out some excess
        water without over-agitating the fleece. You may want to skip this for some fine wools. Be incredibly careful not to burn yourself!
      Submerge fleece in the scour bath you just prepared for 10-12 minutes.
    • Repeat steps above for Scour 3+ until the water looks transparent as noted by the photos above in Bath Progression and no longer has a milky appearance from the lanolin.

Note: Then number of 3% scours will vary depending on how heavy the lanolin is in your fleece.

Note: Dirt will also come out in the scouring of your fleece, sometimes past your lanolin.

  • Rinses:
    • Fill the next tub with a volume of hot water (130-140 °F/55-60 °C) that is at least 3 gallons per pound of wool to be washed.Carefully lift fleece out of its current tub and very gently squeeze out some excess
        water without over-agitating the fleece. You may want to skip this for some fine wools. Be incredibly careful not to burn yourself!
      Submerge fleece in the rinse bath you just prepared for 10-12 minutes.
    • Repeat steps for Rinses until the water looks clear and the soap foam is gone.

Note: If for some reason you are unable to complete the whole process in one go, finish all scouring and move fleece into the first rinse. When you return, continue the subsequent rinses at the same temperature the first rinse has cooled to.

Note: If more dirt removal is sought after lanolin removal, continue with rinses until satisfied or pursue removal during your future processing steps. It is possible to over-scour your fleece and damage it. We are only seeking to use the scour to remove the lanolin.

  • Carefully lift fleece out of its current tub and very gently squeeze out excess water.
  • Optional: Place fleece in a spin dryer to remove further water.
  • Lay wool flat on a screen or mesh to dry. Alternatively, you can dry on towels, making sure to flip wool periodically.
  • Leave to dry for a 24-48 hour period.
  • Store dried fleece in a breathable fabric bag for best long terms results. Preferably cotton material.

Table 1. Scour volumes based on wool weight and % scour.

Wool Weight5% Scour3% Scour
8 (1/2 pound)0.82.411.
16 (1 pound)1.64.823.712.914.2
Lab Protocol Format contributed by Felecia of @one.wip.wonder on Instagram.

Introduction to Common Wool Scouring Agents

In the next series of posts, we are going to go over the results and method that we’ve developed to wash wool in small batches for the home processor. Unhappy with our results by other methods, we set out to find out which scours worked better in our favor and a way to wash wool that depended on listening to your fleece and not the instructions on the bottle. We found too often that we were left with overall sticky fiber, tinged tips, or “pockets” of lanolin left in the fleece where there should be none. This has been quite an interesting series of experiments and fully changed how we approach our wools. Knowing James Perry, also known as LongDrawJames, had his PhD in Sustainable Surfactant Chemistry, we decided to work with him to develop the testing methods and gather his insight. We collaborated on this blog series and below are his writings for the scours we chose to test. None of the materials listed were sponsored and this was a fully unbiased and curious approach.

How Scouring Works

At its fundamental basis, when we scour wool, we aim to do two things – firstly, to remove contaminants such as feces, urine remnants, dirt, and suint (sheep sweat) and secondly, to remove the lanolin. This is an important step in processing wool and very few applications would need lanolin left in the fleece. You should also seek to clean your wools to lengthen the lifespan and ease of use on your processing tools. Lanolin and other contaminants can be incredibly hard to clean off of the teeth of most processing tools. Generally speaking, the suint, or sweat, is made up of salts and other water-soluble organic molecules. Lanolin is a complex natural mixture of greases and oils, containing mostly long-chain triglycerides as well as sterols. Lanolin is naturally water repellent, giving it purpose in aiding the fibers to prevent felting and soaking on the sheep. This means that water alone cannot remove it from the surface of the fibers.

In order to remove the lanolin, we generally employ detergent formulations. Within these detergents, the active chemical compounds which emulsify the grease are called surfactants, a conjunction of surface-active-agents. Surfactants are what are known as amphiphilic molecules, meaning they have a part of their molecule which is hydrophobic, unable to mix with water, and a portion of their molecule that is hydrophilic, which does mix with water.  They are able to lower surface tension between phase boundaries, which means they can allow two liquids which normally would not mix to be granted the ability to mix. Oil and water are a great example. In the case of wool scouring, they allow the lanolin, a hydrophobic grease, and the water to mix.

There are four general types of surfactants and they are named depending on the nature of their hydrophilic group – anionic (negatively charged), cationic (positively charged), amphoteric (both positive and negatively charged), and non-ionic (uncharged). The most important surfactants for wool scouring here are anionic and non-ionic surfactants as these are designed to give optimum performance in the areas we need.

Anionic surfactants are by far, the most widely used surfactants worldwide, making up around 70% of the world’s surfactant use. They are used in almost every single cleaning product. The most common surfactants of this class are Linear Alkylbenzene Sulfonate (LAS) and Sodium Dodecyl Sulfate (SDS), also known as Sodium Lauryl Sulfate. They are mostly used in applications where dirt and stain removal is most important, with LAS tending to be used more in clothes detergents and SDS being used more in personal care as it is much milder to the skin. The major downside of these surfactants in operation is their lack of resistance to hard water. Hard water contains lots of dissolved calcium, which interacts with the surfactants and forms insoluble calcium salts that render the surfactant useless for cleaning. This means you need to add more surfactant than you’d normally need to get the same level of cleaning to account for the amount of surfactant “deactivated” by the calcium. If you are sustainability minded the other major downside of these detergents is their production methods. LAS is produced exclusively from crude oil fractions, and SDS is produced from C12 fatty alcohols derived from palm and coconut oils which have an intensive environmental impact.

Within wool scouring, it is actually the non-ionics which offer the best solutions for lanolin removal as they excel at emulsifying oils and greases. Generally, the most commonly used non-ionics are Nonylphenol Ethoxylates (NPE) and Alcohol Ethoxylates (AE). AE are generally also made from C12-C14 alcohols and a molecule called Ethylene Oxide which is used to introduce the Ethoxylate, a wetting agent and emulsifier. NPE is derived from crude oil. NPE is more of an industrial detergent and is being banned in many countries due to its carcinogenic degradation products and aquatic toxicity. The toxic effects of NPE are a good lesson that biodegradable doesn’t always mean better.

Wool Scouring Formulas on the Market

There are a number of formulations available today as specialist wool scouring agents, as well as some detergents not designed for scouring that people swear by. The four we see most commonly discussed are Orvus Paste, Dawn Dish Soap, Unicorn Power Scour, and Kookaburra Wool Scour.

Orvus Paste is a detergent we see used by many home processors. Unfortunately, it is almost entirely pure SDS. Good for dirt removal, but it has poor hard water stability and does not entirely remove grease. It will do a good job on dirt and is biodegradable, though. Keep in mind that biodegradable is a label that can be put on products even if they do not reach 100% of their materials breaking down in a set timeline. The other issue is its very, very high foaming capacity which means you’ll need a lot of rinses to get it out. Orvus Paste is typically chosen because it is used to wash livestock prior to shows. The use of it to wash the animals makes sense as you would not want to remove the grease from them. Washing wool on sheep in a way that removes their natural oils can cause fleece, skin, and health damage.

Dawn Dish Soap is a formulation specifically designed to clean plates and dishes. It’s a blend of anionic and Amine Oxide surfactants that is often at around 30% surfactant loading in water. In the case of Dawn, the major anionic surfactant is SDS, the same as is found in Orvus Paste. The second surfactant is an Amine Oxide surfactant, which are technically amphoteric, but behave much more like non-ionic surfactants in their cleaning. They are usually very effective de-greasers. In Original Dawn Ultra, or Blue Dawn, you are also going to find some other additives such as a copolymer of PEG and PEI, an anti-deposition agent, as well as Methylisothioazlinone, which is a biocide that can cause acute aquatic toxicity. This makes it not biodegradable. Some formulations contain optical brighteners or enzymes such as proteases which will degrade your wool by breaking it down, so make sure you read the label if you are going to use these. You would not want to get the wrong one and have your wool damaged by it.

Unicorn Power Scour is a formulated blend of surfactants specifically designed for scouring wool. Generally speaking, this is a surfactant blend in water. Surfactants used here are mostly ethoxylated non-ionics which offer best performance for removal of greases, as well as a smaller component of anionic surfactant, which helps remove dirt. Specific identities of these surfactants are not really clarified and it is rather hard to tell which they are using, as there are so many variations which can be sought on the market. The formulation also adds a polyacrylic based copolymer which is a designated anti-deposition agent. This is specifically designed to prevent dirt and emulsified lanolin from depositing itself onto the surface of the wool fibers again and definitely something you want in a scour. Unicorn Power Scour has been labeled and tested to be biodegradable as well, but without knowing what is in the product, we cannot say how much of it is.

Kookaburra Scour is another common formulation for scouring wool. It is also a surfactant formulation in water listed as being natural and plant based. Surfactants used here for de-greasing are almost exclusively fatty acid glycol ethers, which use sugars as the non-ionic group rather than an ethoxylate. This formulation does also contain a very small amount of anionic and ethoxylated detergent and sulfated oil which acts as a surface lubricant.

The Chemistry Behind It

As mentioned previously, the major process which occurs to remove grease from wool is emulsification, meaning the oil and water phases (lanolin and water) are allowed to mix, facilitated by the surfactant. This is not a chemical reaction, but it is a chemical process as the grease itself is not chemically changed by the surfactant.

When a surfactant is dissolved into water, the molecules will remain free in solution. The free surfactant molecules assemble onto the grease using their hydrophobic tails (which are able to mix with the oil). When the concentration becomes high enough, the “pull” of the hydrophilic headgroups by the water is enough that the grease rolls off of the surface and forms a spherical structure known as a micelle. This process is known as the “roll off” method. Generally, people think of micelles cleaning greases, but in the case of detergents this is the actual mechanism of detergency.

The grease has to be fluid enough for the roll off method to work, which is why scouring is carried out at high temperature. The base melting point of lanolin is 120F/48.8C, though it is advised to go a little higher. Likewise, most non-ionic surfactants also work more efficiently at this temperature range.

At a molecular level, this is what is happening when we are scouring wool. But what does this mean on the application level?

Well, when you scour, you need to think of a few different parameters. Part of this is your water temperature, hardness, and volume. You need to have a temperature high enough that you have melted the lanolin. We chose to stick to 130-140F/54.4-60C to truly melt the lanolin and keep the water from cooling between water changes. You also need to consider how hard your water is. Many detergents, specifically anionics are going to suffer from water hardness and you may have to use more than you otherwise might if your water is hard. The bins you use will need to be large enough to accommodate your wool and enough water to give the debris space to gather away from the wool as well. This was all considered for our tests.

What detergent you use is also going to matter. It is generally personal preference as to which scouring agent you use, but we find that one with more non-ionic detergent will de-grease more effectively. We both personally like Power Scour as in our own water situations, which are both, vastly speaking, very hard, this seems to work best. We are also rather fond of the smell and its low foaming capacity that means fewer rinses. Fewer rinses means less water wasted. You will see that it is well reflected in our washing results.

Our next set of posts will be about how we accomplished our testing parameters, their results, and the scouring method that’s been developed. There will be in depth photos for that as well.