From rivbike.com


"Washing and drying it
Do you think wool would have remained popular through the centuries if it disintegrated when it was washed? Do you think the laundry methods of the 1300s were gentler than a cycle in your Whirlpool? Don't make me guffaw.
The fact is, the wool we offer is easy to care for. You can take special care with it if you like, if it makes you feel good and lets you sleep better at night, but it's not entirely necessary. Following is a rough way to care for wool, and then a soft way to care for it, and they both work.
Rough
Soap: Whatever you have, but nothing with bleach in it. Water: Warm Dryer: Warm
Wool laundered this way will shrink about half a size. It won't get wrecked. We'd like to see you treat it with slightly more care, but if you can't be bothered, that's quite all right.
Soft
Soap: Kookabura (we sell it), or Ivory detergent, or pretty much any earth-friendly suds sold by hippies or in a cardboard box adorned with at least one drawing of the earth, and word such as "enviro" and "friendly" and "non-toxic" and "bio-degradable" on it. Water: Warm or cold Dryer: Air. If you want speedy drying, roll it in a towel, stomp the towel, then unroll the towel and lay it flat or hang it up or something.
The main thing is: Don't fear wool. Don't save it for special occasions. Don't look back on a life in which you were afraid to wear wool for fear of wearing it out or something."




Based on that, I used two drops of Camp Suds and it worked great.