I agree with petthefabric, I always prewash my fabric. It removes the sizing, germs and dust from the fabric. It also bleeds out so no surprises later. I serge the edges first so they don't fray. I am amazed how much the fabric shrinks and how uneven it is after it's washed and dried. I used to buy only quilt store expensive fabric. Not anymore, after washing, some of it looked far worse than the less expensive fabric from JoAnn's or Hobby Lobby.