There are a variety of these citrus-based de-gummers/degreasers, but one of the first ones is called Goo Gone and works extremely well on all types of pressure-sensitive adhesives (peel-and-stick.) There are also some knock-offs of Goo Gone that probably do just as well. They can be found in many hardware and Wal-Mart/K-mart -type stores.

If you have any GoJo citrus hand cleaner, this might work, too. I have also had good luck with a degreaser sold at bicycle shops under the brand name Finish Line.

Dean