A summer head cold has settled in and I don't have my usual *zip*. I decided to start a cotton dishcloth from yarn I got off the Freebee table at guild.
I wasn't sure if it was cotton so when I got it home I snipped off two inches and did a 'burn test'. Cotton burns slowly and evenly and leaves a soft gray ash. Polyester or synthetics burn quickly, fizzle and leave a black, crusty residue - like you except from melted glass. It was cotton and I cast on last night.