Some will rub-and-roll into a ball, but some just smear. Presumably, you’re reading this because it smeared.
Odds are, the adhesive was made from some kind of natural or synthetic rubber, and a resin tackifier. You know what rubber is: it’s the stuff rubber bands are made from. The resin is like rosin, a chemical made from pine trees, and also called “pine tar”. It’s soft and sticky. It could also be tackified by terpenes, which are like turpentine.
So, the trick here is to know this material:
- Resins soften when heated.
- Some resins dissolve in alcohol.
- Some become less sticky in water.
- Rubber can soften with oil.
- It likes to stick to itself rather than other things.
So last thing first: if you have the sticker around, try to use it to pick up bits of the stray adhesive. Just press it onto the surface, and see if it pulls up the remainder.
You can also try a piece of tape.
Next up, if the object can withstand oil, try rubbing a little oil into the glue. If the oil starts to dissolve it, you’ve figured out the solution.
There are two broad classes of oils: vegetable oils, and mineral oils. Try both. Mineral oils are things like baby oil and WD-40.
Things that dissolve in oil also tend to emulsify with detergent. If you can leave the object in water with some detergent, that may help clean it off.
Heat will soften the glue, so use hot water, not cold.
Also, there’s a class of adhesives based on silicone. These use special solvents, but one common chemical seems to soften silicone itself: vinegar. If you have used silicone adhesives, you probably remember how they smell like vinegar.
So, try using vinegar on the glue. If that works, you’ve found the solution.
If these don’t work, you may need to resort to alcohol. The main problem with alcohol is that some plastics melt when it contacts alcohol.
If you need more help, try Goo Gone or another mild citrus cleaner. Check the label to see that it’s not too full of naptha, which is a more volatile product that citrus extracts.
The trick to using these is to rub slowly and gently. Don’t press or move the rag too fast. You want the first pass to play down some citrus onto the glue, and the second pass to pick it up.