I prewash all my fabric including the precuts. Some of the fabric like batiks especially bleed only in certain areas. I throw them in the laundry just like my other laundry. I use hot water and a hot dryer. This allows for all shrinkage to be taken care of. my colors still look good. I used to use a basting stitch along the edges of the pre-cuts so they wouldn't fray so much but I got tired of buying pre-cuts and the sizes all inconsistent. Some were correct size but more were shorter and more narrow. Cheaper to purchase yardage and cut my own. I also prewash because of the odor on some of the fabric from the factory.