I wash in the washing machine on hot with laundry detergent and dry with heat. I iron gently. I want everything that's going to happen to happen to that fabric before I use it in a quilt. If I think there are problem fabrics then I use a color catcher and wash again if it picks up a lot. I never starch until I'm ready to use the fabric, because then I'll want to press it again anyway, and I don't want it stored with starch in it. Good for you for deciding to pre-wash. You won't regret it, and if you decided not to...well every week or so there are posts from someone who regrets that decision.