My secret (ssssh, don't tell anyone) low-impact solvent is bacon grease. It works on pine pitch, sticker glue and the like. Let it sit for a while, though.
Avon Skin-So-Soft Bath Oil is next. We have had a bottle around for years and never used it for a bath. I can't stand the smell, but it works. It also works as bug repellant.
WD-40 if the others don't work.