Washing wool: Moving to micro-industrial scouring

I’ve mentioned that I’m working on an extended project involving small quantities of many different wools. Although I’ve been processing raw wool for many years, the demands of this particular combination of tasks are requiring me to reevaluate my habits and discover new (to me) tools and products.

I actually like washing wool, for a lot of reasons. One is that I get to experience the transformation from raw material all the way through to finished object. That’s mildly magical. Another is that the fiber I end up getting to work with—spinning and then knitting, weaving, or whatever—is livelier than mechanically processed fiber. There are other reasons, but those are the biggest.

My old routine normally involved washing whole fleeces in the bathtub, using dishwashing detergent. It’s worked to my satisfaction over time: the supplies can be obtained locally, the wool gets clean enough for me to work with, and the amount of time required for the process is finite. (Although when I was washing some raw yak a doctor brought back from the Himalayas it did seem endless. That was many years ago.)

This new set of requirements . . . well, let’s just say that I have many, many batches to process, and I have other work that needs to get done, so I’ve had to look at streamlining.


First, the bathtub is obviously too big a container for the small batches. My clumps of wool for this project vary in size, but all are relatively tiny. Ideally, they should all be between 3 and 4 ounces (85 and 115g), and many of them are, but they range from 1/2 ounce to a pound or more (15 to 450g).

By checking out the discount and thrift stores, I collected four colanders and four plastic bowls that fit in pairs and also fit in the bathtub. No, of course they didn’t come together! I’d acquire one component at this thrift shop and another at a super-discount store. I carried a tape measure with me to be sure I was making matches that would work. The eight pieces came from seven different locations. The final one was graciously donated by a friend from her kitchen.

Because they’re different sizes, these can handle between 1.5 and 4 ounces (40 and 115g) of wool each. The two larger pairs can handle 4 ounces; the smaller pairs handle less. Because of the shape of the colander and of the bowl, the set on the far right has by far the smallest capacity. In my hunt for containers, I also discovered the magic wool-washing kits that can handle up to a pound (450g).


There’s enough room in the tub for all four colander sets. If I position everything just right, there’s exactly the right amount of extra space for draining the colanders between baths.


At the righthand end of the tub, there are four colanders draining, two deep.

The largest-capacity bowl is on the left, under the faucet. (It’s deeper than the white bowl next to it.) When I run the water to refill between baths, I hold the smaller bowls over it, moving them in and out of the stream of water, and by the time I’m done, the between-bowls flow has filled that big bowl, too, with no unused water going down the drain.

When I select wools to wash in a batch, I choose different colors and textures so I won’t mix anything up. The wools travel through most of the process with identification cards, because some of the fibers are pretty similar (like two samples of the same breed), but those cards don’t go in the tub. I also need to pick samples that fit the capacities of the colanders. I can’t do four 4-ounce samples at the same time.

Cleansing agent 1

The water goes in, first from the tap and then topped off with boiling water from the stove to bring the temperature up (tap water first so I don’t melt my plastic bowls). It’s important to have good, warm water to dissolve the waxes and greases and release the dirt from the fibers.

Then I add the cleansing agent, traditionally dishwashing liquid (Dawn, actually, by preference). I have previously been plenty happy with the dishwashing liquid. It doesn’t get the wool "too" clean. I like a little residual lanolin, because I hand-process. (Mechanical processing requires extremely clean wool.)

But in this new situation I encountered a problem.

Each bath and each rinse involves a 20-minute soak. (The 20-minute time frame is so the water doesn’t cool off very much during any bath or from one bath to the next, but so there’s enough time for the wool to be well saturated with the water or cleaning solution.) This includes:

  • One initial plain-water rinse.
  • Two (ideally) washing baths.
  • Two (ideally) rinsing baths.

Five baths in all, for a total of 1 hour and 40 minutes.

In reality, I go do something else in my 20-minute "breaks," so I sometimes get back 5 minutes late. And it takes some time to drain and refill the tubs, say another 5 to 10 minutes. A complete cycle ends up taking between 2 and 2.5 hours.

In addition, many of the wools, being from breeds not necessarily grown for wool quality, were requiring three washing baths, and now and then four. Any additional bath for a single fiber slows down the whole group (because my brain isn’t prepared to have the colanders more than minimally off-cycle with each other). I found I was up to 3 or 4 hours per set.

Frankly, that’s painful. It puts a huge kink in my ability to get anything else done, and I’m looking at many, many fibers to process over the next several months.

I went searching for alternative, more efficient scouring options. And I wrote some e-mail inquiries to gather more information.

Cleansing agent 2

I ended up getting Unicorn Power Scour to put through a trial. I’ll tell you right now that it’s working. I’ve got my processing time down to a reliable 2 hours, and—even with some interruptions, as well as minor delays because I’ve gotten distracted by trying to get something else done—I can process 12 fiber units (three batches of 4 fibers each) in an 8-hour day. That’s good. My previous record was 7.

Shifting from commercial to small-scale

The biggest trick in using the Power Scour is that its primary market is industrial-scale processing. It was developed to be used at lower temperatures than wool is normally scoured at, and to have a low environmental impact. Another huge plus is that you don’t need much to get the job done. These are good things for me, too, but translating the instructions to my very small quantities was initially challenging.

First I got in touch with folks at the source to ask which of their products would best meet my needs: Fibre Wash or Power Scour? The Unicorn Fibres web site has some instructions for using the milder Fibre Wash on a small scale with raw fiber, but based on the condition of some of the wool in my line-up I thought the stronger Power Scour might be better.

They thought so, too. Fibre Wash can be used on raw fiber but is best suited to finished fabrics. (Unicorn Fibre Products also has a Fibre Rinse that can be used with either cleansing agent. It’s supposed to reduce tangles and static, and to leave the fibers feeling softer than they would otherwise. I made my first experiment with that last night. I’ll be checking it out more in the future.)

For Power Scour, the people at Unicorn Fibre suggested a starting point of a tablespoon (15ml) to a gallon (3.8L) or so of water, and noted that amounts would need to be adjusted for the type of fiber and amount of grease.

The industrial baseline

Along with my supply of Power Scour, they sent suggested start-up proportions that are a little daunting for a micro-scale operation:

"Initial wash: Dose the Unicorn Power Scour at an initial working concentration of 2-3% of the fibre weight. For example, to scour 100 lbs. (45.4kg) of fibre, use 2-3 lbs. (.9-1.4kg) or approx. 32-49 fluid oz. (.95 – 1.42L) of Unicorn Power Scour."

I’m probably going to be scouring 100 pounds, but not conveniently (?) all at once!

Suggested temperatures are in the range of 60 degrees C (140 degrees F) for oily or waxy fibers, and around 50 degrees C (122 degrees F) for less oily fibers, like alpaca or cashmere. Additional washes drop the solution down to 1-2% of fiber weight. The suggested routine calls for an optional first clear rinse for exceptionally greasy fiber, two washes (three for serious grubbiness), and two rinses.

It’s not so easy to calculate 1, 2, or 3% for tiny quantities. The English word "ounce" should never have been used for both weight and fluid volume, because they’re not the same, and while it’s easy and accurate to work with weight on the large scale it’s not a cinch to convert to a very small scale.

What to do? Spend a while attempting calculations. Remember the 1 tablespoon to a gallon idea. Give up on the math, which isn’t providing any reliable guidelines because of the volume/weight conundrum, and punt!

The micro-operation, in a nutshell

I’ve discovered that I still like an initial plain (hot) water rinse for any raw fiber. It always pulls off enough dirt and grease that I think it significantly accelerates the cleaning in the later baths.

I work to keep the water temperature throughout at 140 degrees F (60 degrees C). Initially I used a thermometer to figure out how much I needed to adjust the tap water to get the temperature I wanted.

This is my test run in the kitchen sink. I’ve got a small container of Power Scour for the working process. A little does go a very long way.


Now I just run the bowls half-full from the tap and then top off the rest of the way with simmering water from the stove. One of the big pots is enough to bring the temperature up on all four baths. I alternate between the two kettles, with the one just used coming up to temp while I use the other on the next round.


I gauge the amount of Power Scour to use by the quantity of water/wool in the bath and by how dirty the water looks at the end of the initial soak. There are about 2 gallons of water (not 1) in the larger set-ups and about 1.5 gallons in the smaller ones.  I started with 1 tablespoon to about 2 gallons of water and 4 ounces of fiber (half the recommended starting point; it seemed like enough, based on nothing other than gut instinct), but the wool was getting clean beyond where I wanted it. I’ve adjusted the quantities even lower for almost all of the wools, and I’m still getting fiber that’s plenty clean for combing or whatever I want to do with it. I guess a little low in Power Scour quantities on the first bath, and if I think the fiber’s not getting clean enough I put a little more than I otherwise would in the second bath.

Going back to that first photo, repeated below, the wool on the left would get about 2 teaspoons in its first wash bath, the wool second from the right would get a whole tablespoon (its water is dirtier). The smaller baths would get 1 to 2 teaspoons.


The second wash bath gets about half the amount of Power Scour I used on the first bath. I think I’ve only had to take one or two of the samples to a third wash bath (same amount of Power Scour as the second bath).

At the end of the day

I’m being miserly with the amounts of scouring solution, and I’m getting great results. Wash-cycle times are predictable and shortened. I’m caught up on my washing (which is not the same as "done").

Here’s what 12 fiber samples look like on the stacked drying racks. It’s a good day’s work, and the office smells like lovely clean wool.


The Power Scour seems to be really gentle on both the fiber and me, but remember that measuring spoon up in the temperature-testing photo?

Scoured. The printed type is gone from the handle! The spoon itself is just fine. This stuff seems to know the difference between the extraneous and the essential.

Anybody else have scouring experiences to share?


17 thoughts on “Washing wool: Moving to micro-industrial scouring”

  1. So you’re saying that a little of the Power Wash goes a long, long way? I’m thinking that the 16 oz. bottle should last me a good while.

  2. Yes, a little of the Power Scour (or of the Fibre Wash) goes a *very* long way.

    I have a large bottle because of the size of this project. I’ve washed a lot of wool already and made a noticeable but still small dent in it. I *may* make it through this whole project with the one bottle. That’s astonishing.

    If you’re washing wool for your own spinning, rather than for other people or some other oddness like I’m working on, 16 ounces will see you through a lot.

  3. You like Dawn, I like Sunlight. And for the same reason — never liked scouring my fleece to a faretheewell. But the Power Scour sounds great, although finding Orvus here in cattle/horse country is both easy and rather frugal.

    And I’ve got two of those nifty stackable drying racks (from Zellers, a discount Canadian chain) and they make life in this very small apartment much more amenable for the non-spinning human who shares it with me.

    I should go and get a few more, as I’ve got a fleece that really needs washing: half is done, and the rest sits in my living room, glaring balefully at me…. 🙂

  4. Two wildly divergent bits for you:
    try, in the really dirty fleeces, a bit of salt in one of the wash cycles. Don’t know why, but it’s worked on some of the filthier bits i’ve done.

    Also, save that first, non-enhanced rinse water and pour it on your tomatoes–they LOVE that water!

  5. Wow. I never buy wool unscoured, I’m far too allergic to sheep (but not wool). However, once I got rovings from a small farm which included mohair and 2 types of sheep. I could see no dirt but it was really oily/greasy and smelled a bit more like animals than I expected.

    I used the washing machine and nylon net bags to get the fibers clean enough for me, and even with very careful handling it was pretty much felted when I was done cleaning then dyeing. What a hassle!

    I love buying fibers from folks who process them for me. A local farm has wool/alpaca rovings I like a lot. I mostly use them for feltmaking rather than spinning. I seem to never allow myself to spin. Sigh.


  6. Lynn, one thing about processing your own fibers–even if you only do it once–is, as you’ve noted, the gift of appreciation for those who do good work in preparing fibers for you!

    Kris: maybe when I clone myself I’ll be able to figure out how to run a hose out the bathroom window and over 15 feet to the tomatoes. Otherwise I’d have to traipse through bathroom, hall, living room, kitchen, dining room, out the back door, onto the back step, and down a quarter-flight of stairs to the deck and the tomatoes. The wool washing would come to a grinding halt because I’d be worn out before the end of the first batch was done {wry grin}.

    There’s the ideal, and then there’s human capacity.

  7. I’ve been slowly washing my way through a VERY dirty Cotswold fleece – about a double-handful at a time. This is my first time starting with a raw fleece, and I foolishly let it sit for about a year and a half before starting the project. (Which, I found out later, makes it harder to scour – lets the lanolin and the dirt really embed itself, or something.) I started with a flat-out panicky feeling that I would accidentally felt the fiber, hence the small amounts at a time. So far, so good, but I admit my heart-rate still climbs while I’m working with the wet wool.
    I envy your drying racks – I’m using a huge baker’s cooling rack that I got for Christmas a few years back – never got around to using it for cookies (and now, I never will…), and it’s made a decent drying rack for my wool – but it’s all horizontal, so takes up a lot of room. I’ll have to search out racks like yours.
    Thanks very much for the info on the Power Scour!

  8. Wow, that’s a lot of work per day! the project sounds fascinating though and you’re tempting me with all that wool washing! I’d love to be doing that for a day or two instead of the grindingly slow reading/research I’ve been up to. The power scour sounds fascinating.

    My suggestion regarding the tomatoes? Reserve one bowl of the yucky first soak water at the last wash through of the day. Truck it through the house once. Water one plant. Try that each day. It will be worth it for the plant, whereas if you were to transport all that water? You would be tuckered out just as you say, and the tomatoes would be flooded with compost tea!

  9. Holy Crap! You have just confirmed what I have been thinking – and also shouting – for the last couple of weeks. I’ve tried every kind of wool wash as well as several dish detergents and when I got the Power Scour last month I was singing songs! It works so well with such a tiny bit.
    I too tried to do the calculations at first and now I just use a squirt and get to washing and I am so happy with the results.
    Fantastic! I carry it in my shop now and sell it to everyone I can…poor other wool washes:-(

  10. *Way Different For Apartment Dwellers!!*

    Huh. Still seems like a lot of work, but then, I’m a city girl, and I don’t do this for a living. I use lingerie bags of various sizes, whatever temperature of water comes out the bathtub faucet, and whatever dishwashing liquid is in the kitchen!
    I also like some lanolin, especially in the winter, to keep my hands soft, but waxy things like Rambo and Merino I wash thoroughly.
    I have one of those cheap rattan screens where the panels refuse to stay together, so I perch one of the errant panels on a couple of boxes and that’s my drying rack.

  11. Yes, way different for apartment dwellers.

    I am pushing the limits of my space on this project. When I began it, I actually knocked out a wall between my office and the storage room behind it, because there was no place to put this stuff otherwise. Drastic! Apartment dwellers can’t do that.

    However, the storage room was the only space in the house that wasn’t earning its keep.

    These drying racks are neat because they disassemble into really small packages when they’re not in use. That was as important here as it is in an apartment.

    But if I had a broken rattan screen, I’d be putting that to use, too.

  12. Storage *room*? In your actual dwelling? Wow. We have storage rooms in the city, except they’re in big warehouse buildings and you can’t get to your stuff 24-7. There’s one right across the street from me, but I never know what time of day or night I may get the urge to do something wooly…

  13. interesting, June and I were just talking about problems with scouring wool on a small industrial scale here. There is nowhere to do this in Lith, so wool is sent to Poland. I will probably write about this when i get home.

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