There hasn’t been a lot written about caring for wool. One of the things you often see on labels is, Do not wash, Dry Clean only. Dry cleaning will certainly clean wool, but it fills it with chemicals that smell bad and removes the lanolin and oil. And if you are an outdoorsman, you don’t want to do that.
All wool can be washed. How you go about doing it is important…but it is simple. Forget the wash machine and dryer. All wool should be hand-washed in cold water with a gentle soap. We use Charlie’s Soap, which is totally biodegradable and unscented and works particularly well on wool and silk. Woolite has been around for a long time and works well, but it has a fragrance in it, and I’d as soon not have that on my hunting clothes.
A big container, like a bathtub, that will hold lots of water is best. Dissolve the soap in the water and push/slosh your garment up and down, back and forth, pushing the water and soap through the fibers for a few minutes. It doesn’t hurt to let it soak a bit. Drain the water and refill the container with clear water and repeat the sloshing action, rinsing the soap away (which you’ll not be able to see.) Press as much water out of the garment as possible, but DO NOT WRING or TWIST.
I lay the garment between two dry towels and press as much of the water out as possible. Then I carefully “block” the garment, which amounts to gently stretching the fibers back into their original shape, pulling vertically and horizontally. Sometime two people gently stretching trouser legs and long sleeves works well. You may feel the wet material move a tiny bit, and that’s all you are trying to do. I may do that a couple of time as the garment dries. Hang or lay the garment where it catches the air, but not the heat. Honestly, I have a closet full of wool clothing…some of it 50 years old…and I wash it all and none of it has shrunk.