I can't recall the consensus of the CR wool-bearers, but here's my two bleats worth:
I wash all my wool (and all my other bike clothes) in lukewarm water with a bit of Ivory dishwashing detergent, after which I rinse each article several times. (Woolite is another choice, but I think any mild detergent would do.) Then I hand-squeeze it dry (not wringing it) and let it air-dry; if it's big enough, I usually lay it flat over the clothes rack so it won't stretch.
I try to wash it right after I've stretched after a ride so that nothing gets a chance to set in for good--or bad!
nath dresser spring green, wi (mid-40s today! should've gone for a ride, but I used the nice weather to work on the car instead)