I have heated old crap tint & peeled off with a razor blade. You will still have a lot of glue to clean up but it will come off with some ebow grease.Do it in an area with lots of fresh air. The ones I have done the old glue stinks pretty badly, but will go away in no time.

1957 Chevrolet 1/2-ton Stepside LB in the Gallery
My Photobucket shots

The person who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself." - John Stuart Mill (1806 - 1873)