My wife found some stuff at Kmart, I think, that is supposed to soften the glue on that stuff. I hear it works better if you spray it on then cover it with plastic and let it sit in the sun for a few hours. I de-tinted our old Civic with a simple old sraight edge razor blade. The spray solution helped a little but the razor was the ticket. I don't think front windows are any different on the inside than side windows so I'd bet you could have that off of there in about 15 minutes of scraping.

Hope this helps
--
Bob W.
16 Volvos ('58-'91)
445-544-122-240-740
Four turbos