Stickers/decals over the clear are, like everyone says, easy to get off by heating with a hair dryer and slooowly pulling off. Keep them warm and moving, and they often come off intact. I try to get bike shop decals off intact and put them on my toolbox.

Water-slides will self-destruct, and I use a thumb or finger nail, get 'em off and use a little rubbing compound to erase the evidence of where they once were.