Ok so duct tape on vehicles sucks!
When i bought the blazer it had duct tape residue on the rear (the dudes ex broke out his back window)
It was finally "warm" enough outside, and not snowing and i had the day off so i decided to tackle the duct tape.
First i used bug and tar remover, the stuff i took off the badge residue on the bonneville, and that didn't do anything, so i took out the big guns, i got my bottle of Goof Off, and with a bit of elbow grease, a few cuss words, and two rags, the duct tape is gone. (so is half the clear coat but thats another story :P ) Yay!

So DON'T PUT DUCT TAPE ON YOUR CAR! :P

pics:

before:
DSC01377.jpg

after:
DSC01397.jpg

Next up the stupid dealer sticker.

You missed all that red residue on the rear window.