I only use professional, permanent dyes on my wool, however I advise always hand-washing your fine knits in cool water and a gentle soap no more than once a year and dry flat, no matter the fiber. Even with a Superwash wool, hand-washing will lengthen the lifetime of your item and allow it to keep it's shape much better. If you DO want to put your pieces in the dryer, use the delicate cycle and I usually put a few other items or some dryer balls (wool balls to help things from sticking to the sides of the dryer) in with the item. You can also partly dry in the dryer, and then finish laying it flat to completely dry.