You can buy plastic scrappers. They work the best and be carefull with the heat gun. If your not used to using one I would suggest using the hair dryer. They get plenty hot enough to get stickers off easier. And once your done and all the glue is off get some wax on there.
i just used a heat gun and it came right off. no need for good gone or anything of the such. then i replaced them with black ones right after that. used a little bit of water and a rag but other than that no goo on the truck was left.