I always soak the batting in warm water in my washing machine, spin it to get most of the water out, and then dry in dryer. It doesn't ruin the batting - I do this with both Hobbs 80/20 and Warm & Natural. I don't want shrinking AFTER I quilt. I also prewash all fabrics to be sure the dyes are set, and the fabrics are shrunk as much as possible. I don't like surprises when my quilts are finished - learned from sad experience!