I'm well aware of the pros and cons of "acid free" for everything touching our fabrics, but I'll tell you what.. I really don't plan on these lasting for hundreds of years.. and how many keep fabrics in wooden or "non-acid free" cardboard, or plastic boxes.. which can give off chemical fumes..... If you do all of those and are making museum pieces I can understand worrying about it. I'm not.. I'm just making fun and pretty things to last for a while and keep friends and family toasty for a bit. So by choice I'm blatantly using what is available..I don't think the boards that fabric comes on in shops is acid free either is it?