I have a Wagner heat gun, It works excellent. Just don't leave it in one place for very long, keep it moving.
I've always heard lighter fluid or WD-40 is supposed to work, but the heat gun works a lot better.
"Sticker Off" works ok, but I have always had good luck with lighter fluid & WD40. Acetone will melt the sticker off of metal parts but is a messy clean up.