I used a razor blade, actually still have a bit of followup to do with tiny, almost unnoticable scraps hung up on the defroster wires, but it's 99.9 percent gone. I just used the razor blade to peel up a corner and then used it to help separate it from the glass as I peeled, trying to get big sheets. My way was a PITA, it took me 5 hours to do two small side windows and the back hatch. Also, definitely don't use a dull blade, you need it to be as sharp as a razor .

As for defroster wires& razor blades, if you're careful you won't damage them. But I slipped once, and stripped the outer insulation off of about a 16th of an inch of it. Didn't cut through the wire, but I bet that when winter comes around, that one wire won't work.