Vinyl sticker are no problem. But sometimes you'll have those clear stickers that leave most of the adhesive on the frame, and only the smooth plasticy stuff comes off.
I hate that. I've found Goo Gone to be lacking... What did work, was to take a piece of very tacky duct tape, place it over the sticker residue, smooth it down real good, and peel it back off. Repeat a few times. Usualy, the adhesive on the duct tape is stronger than the residue left on the frame, and the duct tape picks it up. It take a few tries, but to me it beats Goo Gone hands down.
Good Luck.