Don't know if anyone replied about the cotton question or not as I did not have time to read all 18 pages of responses. Anyway here it is:
The way to test fabric to see if it is 100% cotton or synthetic (poly, rayon, nylon etc,) is to cut off a corner of the fabric and light it with a match (or cigarette lighter) and let it burn for a couple of seconds, (don't burn the whole corner piece). After you put the fire out, the cotton will still have a soft edge where it's burned. The synthetic will have a hard, plastic feel to the burned edge.
Ellen