I always wash my fabrics before cutting now. I was once making some doll clothes with unwashed fabric. Went to press pieces of red with steam and ended up with dark pink spots all over my ironing board cover. Then I had to wash it because I was afraid the color would get on other clothes/fabrics. Well, when I washed the ironing board cover it shrank and wouldn't fit on the ironing board anymore. So after all of that I don't take chances!