I had never prewashed before, but, having read other blogs about this, I decided I was going to start. I zig zagged the ends of my fabric, to help cut down on fraying. I put the fabric into a pillow case, and put a shout color catcher in the bottom of my washer, washed using my regular laundry detergent. Hung to dry. Ironed using spray starch and love how the fabric is now. So much easier to cut