i usually find wd-40 works really well to loosen it up including residue, just keep it away from the edges of the label...those are what absorb liquids the fastest on most labels. once you have the main chunk of the sticker off if necessary use a small flathead screwdriver to lightly scrape away the remaining residue. then do another quick cleaning with some alcohol on a q-tip (helps to get rid of the slimy feeling of the wd-40) and then a damp mr clean magic eraser or cloth to clear everything away. i've done that with quite a few labels without doing any major damage...the worst you can get is a stain if you let much of the liquid hit the edge of the label, just make sure to wipe up anything that goes near the edge really quick with a dry cloth or towel.
the first 2 pics in this album show how well this works:
https://www.facebook.com/...p;type=3&l=b74e8bc032