Well you can try two things that should work (to my knowledge):
1. Use some kind of mild solvent to get the glue off -- like alcohol or the thing they use to clean marker boards -- be careful though, you don't want to get the paint off as well, right.
2. Try toothpaste -- a lot of people understimate the power of toothpaste
, it's actually quite abrasive --- I use it to clean after I change the stickers on my laptop for example -- again, try not to ruin the paint. You might want to use a toothbrush along too
Before you do anything try to see what the effect would be on the paint by trying on some spot that is out of sight, and you can touch-up if smth goes wrong.