use a credit card and goo gone, works amazing, better safe than sorry and works just as good. Also noticed no one has said this yet but if your badge has been on for a while its gunna leave a shadow of where the badge was. Grab some polish, even applied by hand to get rid of that ghost and make it nice and even, like it wasnt even there. Then throw some wax over the top and your set, shinny and badgeless

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edit*, heres a picture of mine from a while back, right after i took another badge off, looked completely clean and nothing on the paint. Threw on fax and this is what i saw haha. I think it looks pretty cool in the pic though.