I always wash and dry any fabric I buy. Because years ago I made a nice pair of pants out of double knit fabric - everyone told me that that type of fabric does not shrink. WRONG!!!!!! My slack shrunk 1 inch in length when I washed them after I had worn them and they needed washing!!! So, since then I wash and dry every typed of fabric that I bring home -- IF it is going to shrink - I want it to shrink BEFORE I cut it out.