Goo Gone is a commercial product that works, but just about any oil will work. You can use WD-40 or vegetable oil, rub it in well and rub the adhesive away.
Compund W might do the trick. But do NOT use a lot, as it would also remove the vehicle's paint finish.I had a scrape on my driver door and I used some Compound W on it. Now, you have to get about an...