I would suggest this method:
1. hot water towel, get as much as you can peel off first.
2. hot semi-soapy towel(hand soap or ajax liquid), to help break down the proteins in the gum. no need to soak the towel.
3. repeat step one until the gum is completely off.
don't wait til the gum is black, it'll be too hard to get off
good luck.
