I just did a burn test on a sample from one of the $5/bolt Walmart fabrics and it was definately not 100% per cotton. It burned quickly with black smoke and the ash was hard. Forgot to notice how it smelled...I was too busy making sure I didn't set off the smoke detector. The piece I tested was tan with a darker tan fine marbling on it in case anyone else has the same fabric. I bought two other tonals on the $5 bolts and assume they are the same.