I was thinking of buying some of the corrugated plastic but if you say the foam core works well and is cheaper, I'm in. I also have some very heavy cardboard (not corrugated) that I'm thinking of using. The only question I have is whether it will stain the fabric or break it down faster since it's not archival quality. I picked it up for free during state testing while volunteering at our local school. I planned to use it for templates but there's so much and it's already cut to size. Any one have an opinion or suggestion? Would you use it for fabric storage?