Check with a local body shop or two. one of them may have a decal/glue remover or you can buy one to go onto an air whizzer. It's a soft rubber cup that spins and contours on the body where the goop is. the friction removes the adhesive and doesn't damage the paint.
Removal tools look about 1/2 way down for the tools. They work great.

-Todd
1987 Montero 2.6l 5-speed (Sold...but I still miss her)
2008 Jeep Patriot Sport 4x4