Investigations into Fabric
I'm more putting this here as a linkie for me, as I have a number of mystery fabrics myself....
http://wewilsons.blogspot.com/2009/02/experiment-fiber-content.html
It's a description of someone doing the burn test on her mystery fabric collection...
Nifty. One year, one of the highschool students did her geology paper on this sort of thing -- except with gemstone cabochons. She tested a slew of cabochons under Heat, Cold, Battery Acid and Blunt Force. It was pretty interesting, too...