The hot air gun technique works pretty well (just don't melt your seals! ) and a good fresh razor blade. As the other guys have said,decent glass cleaner and razor takes care of any residue. As Alan said the old gum stinks!
1950 Chevy Advance Design 3100 in Scotland In the Stovebolt Gallery More pix on Flickr. I've definately got this truck thing in my blood ... my DNA sequence has torque settings "Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.