How to remove cIing sticker stuck to back window?

My college name was on the inside back window at the top for several years. When I tried to remove it, the plastic came off but large chunks of the name were left behind. It looks as if it mildewed between the words and glass but that is impossible so it was just a break down of the colors from the heat I think. My car has the orange lines on the back window for the radio antenna and defroster. Any ideas on how to remove the words without damaging the antenna and defroster? I tried corn oil - no luck. Thought about a razor blade but I have been told that the orange lines are in fact a plastic coating itself. Many thanks for your experience and ideas.