Thank you for posting the link to this helpful Web site, Tamar. I've often wondered how to determine what kind of yarn is what in a thrift store. Do you think the managers will mind if I take a lighter around and burn parts of their sweaters to figure out their yarn make-up?
Still, good to know. I think I ended up swatching and washing the last unknown yarn I had. I don't think my test was very successful, though.