Wool test?
 

I know about the burn test for cotton vs polyester fabric. Is there a similar test for wool, either yarn or fabric, to determine if it is 100% wool or if it has poly stuff mixed in?

Thanks!

Cotton is pretty clear cut, with clean ash. Any 'hard' residue means something has melted, so poly or other man made fiber is in the mix. Most of the other fibers rely on odor, which is kind of subjective. If you Google "fabric fiber burn test" you will get lots of hits. Here's one

http://www.ditzyprints.com/dpburnchart.html

100% wool will not hold a flame,,i.e. it will self extinguish. Also, it will smell like burnt/burning hair.