When I first picked up my car two years ago, I bought a can of Goof-Off for this very purpose. But then it seemed like it almost always leaves a faint rectangle where the sticker used to be, and I'm a little hesitant to remove it. I'm not sure if it's better to have something unattractive that most people would never notice, or something that looks like there's something wrong or something missing. I guess I still haven't made up my mind on this...