I forget the name ( might be 3m ) but there is an adhesive remove I use for any glue residue. Works great, and actually dissolves itself after a few minutes. So you're not left with chemical residue. Works fast. All you need is some form of scraper and you're set.

You also need to tape off all the holes from the inside to avoid have the remover leak through the holes and damage the interior paint.

I read somewhere that that would be old hide glue and warm water and soap is best...could be totally wrong.

Mitch

For old hide glue, use alcohol. It will crystallize the glue..

It depends what type of shell you have. Some, like Rogers and Ludwig pre 80's are a pain to deal with. I found that using Lacquer thinner works best in some cases, not in other. Never tried 3M but I have heard of a product only available in Canada called Glue Buster made by surf pro. Apparently takes care of any kind of glue.

Here in California, where everything is almost prohibited, is not available.

But whatever you do use a type of chemical that evaporates quickly and leaves no residue. To make it effective since the surface is round and the liquid will tend to fall off and evaporate, place a cloth on the shell and soak it with let's say lacquer thinner, then place another cloth on the soaked one. Leave it for about 20 minutes. The glue now should come off very easily with a plastic scraper.