If it's still well and truly glued down, meaning that the glue hasn't dried up and the label is about to fall off the shell on its own, you could try steaming it off, you know like they do when removing wall paper. The steam would soften the glue enough to allow it to be worked with again and you should be able to remove it in one piece then using a thin putty knife with little to no damage. I did this with a paper label on a Gretsch snare drum to good effect and reattached it using the 3M fastbond contact adhesive.

Man, Mikey! I was about to ask for the same thing. I have a Red Wine Ripple set that someone painted brown inside the shells. (Tags included)...I need to take off the tags, strip the paint and the repaint the shells with the correct flat grey...talking about projects...