you can use goo-gone or W-40. and scratch it off with a old card or just wipe it off

 

they have rubber wheeles that you can mount ontoo your drill.. its like a big giant eraser... it worked really well when I did my car...

 

hot water or a blowdryer should make it easier to rub off with a credit card or something of that material. if there is still a lot of adhesive left, use dental floss too. then clean it up and wax it and you're good to go!