QUOTE (Tweel @ Aug 7 2008, 12:32 AM)

On most surfaces, I'd use UnDu Sticker Remover (aka "Scrapper's Solution by UnDu") -- it works better and stinks less than anything else I've tried (e.g. naptha, "Goof Off", or lacquer thinner). I think Best-Test "Bestine" rubber cement thinner is the same thing: heptane. If they're in your area, I've seen UnDu at Menard's and Bestine at Michael's.
If Ron says solvents are OK, they probably are, but for myself, on something like hard rubber, I might first try pulling off as much of the paper as possible, saturating the remainder with vegetable oil for a few minutes, then rubbing it off with a cotton cloth.
-- Brian
Lacquer thinner!

Lacquer thinner will most certainly damage many plastics. I found that very early on as a kid. I would also avoid using any of the "orange" solvents or cleaners because I've found that they're not as benign as they would like you to think.. They also can and do damage plastics. I don't know what their effect is on hard rubber.
Naptha, which is what most lighter fluids are, evaporates very quickly. It's the only thing I can say with any certainty, that I consider to be safe for use on pens. I've used it for the nearly 20 years that I've been collecting and working on pens, and have never had it harm a pen in any way. I can't say the same thing for other solvents or things that might remove adhesive.
Brian is right though, you should try to remove as much as you can without the naptha. Most people don't know that a a little heat from a hair dryer (where have we heard THAT before?) will soften the adhesive enough that a label can be lifted. Works on box labels too.