For stubborn tint:
you need 1 blk trash bag, 1 blade,1 spray bottle filled with amonia, 1 mid day sun.
Cut the bag to roughly the shape of the window, spray the amonia liberly on the tint, place bag on tint, pressing all bubbles and wrinkles out... leave in sun for 20 min.
Remove bag, spray again, scrape. It will come off like tissue paper.
edit: sorry about typos.. Im sleepy//