Tint Removal

Does anyone have any suggestions for removing tint from the rear window? I didn't have a problem taking it off the side windows, but the thing that's making the problem for the back window is the defroster lines. Does anyone know how to remove tint without screwing up the lines, or should I just not worry about it and get a kit to redo them? I don't know how much of a hassle or cost that would be, and living in FL, I don't use the defroster all that much, but I still will need it sometimes in the winter so I really should try to keep it/replace it.

Thanks in advance!