I would recommend a rotary tool with a pin stripe removing attachment. This tool is a disc of rubber similiar to a pencil eraser. Spin it up to 3000Rpm and gently run it over the adhesive. It scrapes it right off without scratching the paint. It is truly amazing.

I took 10yr old pin stripes of an expensive Jaguar with this tool in 20 minutes. Goo gone was taking me about an hour per foot of stripe.

Get it at an automotive paint supply store.