Wash or pre wash it is a personal choice. But what about the pre-cuts they are putting out. If you don't wash the 2 1/2 inch fabrics, do you then not wash the backing? My theory is to steam iron the pre-cuts and do the same for the backs. Then wash the quilt in Synthrapol. It says on the the bottle that it has a unique characteristic of keeping loose dye particles in suspension, thus preventing backstaining. Can buy this at any art store that sells fabric dyes. So I wash all or most of my fabric in hot with the use of this product. And believe me some of the kids quilts I have made have been pretty colorful. Mother's have never complained. I also alway give a bottle of soap for washing quilts as a gift with each one given. Some use it, some use just regular detergent and never had a problem. But all wash in warm water as I have told them to.