Originally Posted by
Shelbie
Burn a tiny piece. Cotton burns to ash while fabric with polyester will blacken and bead. The scrunch test will also work.
Cotton will crease while polycotton creases much less. Iron a piece. Polycotton will smell, change colour a little and begin to shrivel a little with a really hot iron while cotton does not.
This is very helpful -- I get fabric donated to our local chapter of Project Linus all the time, and sometimes I really can't tell on the solids. I have definitely noticed the smell, though, and wondered if that was an indicator. Thanks for letting me know that it is!