I have to disagree somewhat about plastic shelving. Most of the time, for most fabrics, it will be fine. However, some fabrics, especially hand-dyed fabrics, can change color when in prolonged contact with plastics. This happens because of the VOC's (just a fancy term for the gases that slowly leach out of plastics) that are in plastics in small amounts. If you want to use plastic shelving, try making sure that the area is well ventilated, and that you use a nice, thick barrier between the fabric and the shelf - like the acid-free cardboard suggested here, or a few layers of acid-free tissue paper. How do I know this? Aside from being a chemist, I had some fabric change color on me where it was stored in contact with plastic. One section of a folded fat quarter that was supposed to be purple is now orange. 18"x22" of purple, with a big orange rectangle in the middle! I avoid plastic now whenever possible.