connie d, you will get a better response if you start a new thread with rag quilt in the title.
I think many quilters use 3 layers of flannel for their rag quilts and do pre-wash their fabric (a couple of times) because flannel can shrink a lot. Some flannels don't shrink at all, but some shrink significantly. Although I don't normally pre-wash quilt fabrics, I would do it if I were making a rag quilt.
Cutting the "rags" is hard on the hands. It's worth investing in a special scissors for this. Also, be aware that the first and second wash of a rag quilt can generate *tons* of lint that can actually clog up your washer and dryer. Not sure about the washer, but with a home dryer it's a good idea to stop every 10 minutes to clean the lint filter.