Originally Posted by bearisgray

One can do a burn test to see if the fabric contains a synthetic:

One only needs a piece of fabric about 1/4 inch wide by about 1 inch long - doesn't take much

Hold it with tweezers in a flame - I prefer a lighted candle - make sure that you have an ashtray and a glass of water handy

If it is synthetic, it will burn with black smoke and leave either a crispy or gooey ash.. The residue stays hot for a long time, even after the fire is out.

All cotton burns with only a little smoke, and leaves a very powdery, soft ash.