Anybody have any secret tips for removing old window film?

Find the corner and pull like a mad man :D Seriously though you need to find the corner or make a small cut in it with a rasor blade and then pull it at an angle.... When you got it all off clean the glue residue with windex and steel wool :redspot

steel wool on the windows? Really?

You don't need the steel wool. I just did it and if you soak it with Windex or 409 (let it sit for a minute) you should be able to scrape the glue off with a razor.

Spray the film with a 50/50 mix of water and amonia. Then apply a heat gun of hair dryer from the exterior. If its more than 10 years old it WILL NOT come off in one piece. It will come off in millions of pieces making your life hell. No matter what it is not going to be fun. I almost ripped out my rear window to take it all off. If you get one of the razor handle tools it will be easier.

yeah be careful not to cut the defost lines with the razor blade. I also had to take my old tint off because it was purple and changed it to black. I did it the exact way CJ said it. It will make your life alot easier.

yeah be careful not to cut the defost lines with the razor blade.

Yeah forgot to mention that. Thats the part that made it so difficult. I have no patience so I ended up slicing one of the lines.

The black tint from the 80's early 90's was plastic tint which faded to turn that purple color you often see on POS's. Now a days the tint is aluminum and does not fade and comes off generaly in one piece.

so that purple-ish hue doesn't denote royalty?