I would not use them for quilts. Cotton does need to breath or it can begin to break down much the way a compost pile does. It is a natural material. Cotton against any petroleum product or wood product can cause a chemical reaction and is usually what causes the rusty looking marks on old quilts. I store mine in cotton pillow cases in my closet and then air and refold in a different way every 3-4 months. They were all made by my grandmother in the 20's-40's.