Hey Ken get some heavy duty glass cleaner, preferably with amonia, some fine grade steel wool, a pack of razor blades, and be prepaired to gag as the glue comes off of the windows.

Took me about an hour to strip the 5% limo tint off of my old red EF. The darker/better the tint is the easier it comes off in huge sheets though. If the tint is already purpling/peeling you might be in for a really shietty time.