Washing fleece

Washing fleece is a process people find intimidating, but it's not fundamentally harder than washing a sweater. The most important part is being familiar with the intricacies of felting, so you can avoid doing it inadvertently to your fleece. There are good arguments for doing as much of your own fleece processing as possible, but in my mind none so important as the mud-pies sheer fun of being elbow-deep in a nice skanky fleece.

It's important to wash fleece pretty soon after you get it. The wool itself obviously can last centuries :-). But as time goes on the lanolin hardens, and gets more difficult to remove thoroughly. Color can be affected, and any stain can spread or organic bits ferment. And raw fleece attracts moths much more than clean one. You may keep a pound of low-quality raw fleece in your closet as a moth decoy, but if you want to use a good fleece you should wash it promptly, even if you don't get around to the rest of it for years.

The process itself is very simple, at least very low-labor. It's most similar to bread baking, where a few fits of activity are distributed over a relatively long period of time. If like me you have a tendency to get absorbed into other things, or to get genereally distracted, you might need a kitchen timer to help keep you on track.

I like and very much recommend using net sweater bags, also sold as lingerie bags. They're made of strong nylon net, and allow you to keep the fleece under control, so you don't end up sloshing about a lot as you transfer it, and so abrasion from that is minimized. I find that 3 regular-size (30x40cm, 12x20") sweater bags fill the largest washing machines I've used, and that 4 are the maximum that'll fit into my large Victorian bathtub. Fill bags loosely with fleece, if you stuff them too much water won't be able to circulate as much as it should and you won't get as good results. I find that washing more than a pound or two at once is counter-productive - the process is less efficient if you can't provide enough of a water/fleece ratio, and I don't have room to dry more fleece than that in my apartment.


Sheep are nice animals, but they're not very hygienic. A raw fleece will come with all kinds of extraneous stuff, even if the sheep was covered to keep it cleaner. The burrs and thorns and foxtails and twigs can all come out with carding and manual picking, they're not very bothersome unless there is really a lot of them, and then they're merely time-consuming. The dung and other bodily excretions are fortunately water-soluble, and the larger bits can be picked off by hand before you begin. The dust is no worse than in other places, and is usually held in place so that even allergic people don't have much trouble with it. But the grease (lanolin) is the main thorny problem.

Lanolin is a very interesting part of the sheep. It has some very functional aspects, as it flows along the fleece from the roots it brings with it much dust and dirt, and so it contributes enormously to keeping the fleece clean as it's on the sheep. It's also a fine moisturizer, keeping the sheep skin dander-free and the fleece soft, and in turn helping your hands as you touch it (or buy it refined in expensive lotions). Some relatively rare people are allergic to it, but otherwise it's on the whole a very fine product from Mother Nature.

The problem comes when you're getting potentially several pounds of dirt-caked lanolin at once, perhaps hardened by age. Lanolin being a grease dissolves best in hot water, and is helped immensely in that way with generous amounts of detergent. But there is a troublesome tendency, which is that lowering temperatures can make the lanolin re-form as a slightly different solid, a much stickier one and a harder one to get rid of. So you need hot water, as hot as possible (you may have to adjust your hot-water heater thermostat), but you need to get on with the process without letting the fleece sit in cooling water, or the end product will be worse than what you started with.

What causes felting in wool is abrasion, not heat. Which means you must handle your fleece very gently while it's wet, in fact it's better not to handle it at all. You lay it on the soapy water like a baby, without any wringing and scrubbing, even without any idle swishing. This allows you to use extremely hot water for efficient cleaning without any untoward effect.

Soapy matters

Choice of cleaning agent is important, as you can greatly facilitate felting with the wrong choice. Basically, soap is out. Alkaline pH helps open up the little wool scales, and you're just asking for help in felting. Soap is by definition alkaline, so it's best avoided, reserved for your deliberate felting projects. In the same vein, Woolite is a mythological wool-washing gentle soap, except that it's if anything even more alkaline than soap and not gentle at all, your fleece will be harmed if you use it.

What you really want to use is detergent. Detergent is a surfacting agent, which means it breaks grease down into small particles, and allows them to be washed out by water. The best for our purposes is Dawn dishwashing liquid. Nice pH, very similar composition to the much more expensive synthrapol that you buy in reputable dye stores. It's both very effective and very gentle. It's what they use to wash birds caught in oil slicks, so that tells you that it can get rid of a bad mess, but also that the fragile feathers are not stripped to uselessness after treatment. Now the weird part is that the flavor/color of Dawn matters some :-). The original blue is the best in terms of avoiding felting, it really keeps those little scales closed. The much-lamented yellow (now unavailable) was a dead ringer for synthrapol, so your colors would never run. Who knows about the other flavors. But on the whole, if you can find blue, use it, especially if it's 'original fragrance'. The concentrated version is OK as far as I can see, you just need to use less of it, and I've also had good luck with the 'fast acting' version, which does act faster but doesn't seem to act significantly different.

In a pinch, other detergents will do. Dish detergents are a good place to look, as long as you take a good look at the label and make sure it's detergent and not soap. Try to avoid a lot of extraneous ingredients, perfumes, antibacterial junk, whatever. Regular laundry detergent and shampoo are fine options for sweaters, but usually are not strong enough for lanolin.

Washing by hand

Run very hot water into a bathtub/basin/sink. Just hot water, nothing else - hot water pouring energetically onto or around fleece can generate enough turbulence to felt it. When your container is full, add a generous amount of detergent. I use at least ½ cup of Dawn per bathtub-full. Use about a third less if you have the concentrated version. But if in doubt use more... You're allowed one quick swish there, to mix it with the water, but not enough to foam it, and before you touch any wool. Lay your fleece in bags down on the water, and do nothing else. Maybe gently lay your hand on top of a bag and weigh it down so it gets wet faster, but really that's not necessary. Go away, resisting strenuously the urge to swish anything. Swishing is abrasion! The water and detergent will get to every apparently neglected lock, given time and patience.

Let soak a suitable amount of time (generally 15-20mn for a bathtub, less for a smaller container), you want to have given the detergent enough time to work but you want to make sure your water hasn't cooled noticeably. It's much better to have more washes than to let the water cool in any one. Come back and gently take the bags of fleece out of the water, allowing them to drain and then laying them in another smaller container, whatever is handy while you refill. Let the water out, rinse out the tub, then pour more clean hot water into the bathtub/container. This alone can take almost as much time in my bathtub as it does to do the soaking. Repeat the process, with or without detergent.

I usually do two detergent baths, because I think one is generally not enough, but I don't bother to rinse between them. Use your judgement here - generally merino is very greasy, and churro is not, but evaluate your individual fleece's degree of dirt and particularly of greasiness. A filthy merino encrusted in old grease could well take 3 baths. Lay the bags of fleece back down on the water. Wait again. When you're rinsing, the soap will disperse on its own, also in about 15-20mn. I always do at least two rinses, I like to see clean water before I'm through.

Also, if your water is very harsh and alkaline, a small glug of vinegar in the last rinse may be a good idea to keep your fleece soft. Some people advocate conditioner for wool as a rinse, but that's another fallacy. Conditioner tends to be too alkaline for wool to be happy in the long term, and to be full of extraneous ingredients that'll only attract dirt to your fleece faster. It's never going to make rough wool feel softer.

When you're done rinsing, let the fleece drain a bit. It's easy to hang the sweater bags from the shower head. Or a colander is fine, wool is hardly poisonous, especially if its only possible contaminant is dish detergent. But I find it well worth my time to then give the fleece a spin in a salad spinner. This takes a good while, as only a few handfuls of wool fits into it, but it saves immense amounts of time in drying. Or if you have limited access to a washing machine, it'd be good to spin the fleece at this point.

Machine help

If you wish to use a washing machine, you'll need one of the top-loading, water-guzzling, SUV kind of models with a control panel accessible. A laundromat rarely provides that kind of fine control, you usually get stiffed for every filling and can't get directly to the spinning cycle. You're basically using the same procedure as the manual one above, but you're using the machine as a large water container, no agitation is permitted at any time, and you're making judicious use of the spin cycle.

Fill the machine with the hottest possible water, then add detergent (½ cup of Dawn). You don't want the detergent in right off, or foam will spew out of it like a horror movie. It's helpful if you move the dial to 'spin' right after the machine is full of water, before you do anything with wool. This will prevent any spastic accidents, the top falling and allowing agitation to start. Kiddies and kitties have been known to cause this to happen as well, even if you're not usually as much of a klutz as I am. And even a few 'whoosh whoosh' can felt a delicate fleece irretrievably.

Then lay the bags of fleece on top of the water and let it soak as in the manual version above. Take it out, then spin the water out, repeat the process to rinse. The big advantage of a machine, and one that you can do even if otherwise hand-washing, is putting the entire wet fleece in the empty machine and putting it through a spin cycle, this will get it to barely damp condition without any abrasion.


You're done with the heavy labor. Take the fleece out of the bags, and lay it on one of those sweater racks with netting, so it dries faster. Try to keep the kitties away from it, they love clouds of clean fleece, particularly when they're padding a little kitty-size hammock. Every 12 hours or so, test it, turn it, fluff out any tight clumps. Keep in mind that damp fleece is still vulnerable to felting, so don't be brutal. Drying time can be 12 hours to several days, depending on your climate.


First published: 12/15/02
Modified: 6/15/06

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