I wash all that yard goods I purchase and dry them to almost dry then hang them up and finger press them as I take them out of the dryer love the selvedges if I don't tidy them up a bit. I try to do this when I bring them in the house. Then, they are ready except for ironing with starch when I begin a project. Now, I have purchased charms, layer cakes, and jelly rolls and followed most of the advice saying "don't wash". I like the convenience that I don't have to cut them however, I found when I ironed them while piecing, some of the strips from the jelly roll shrank almost 1/3" after I had pieced them, was not happy. Fixed it but learned. Still I will buy them but learned...a lot.