Drive your car to a spot that receives full sun after removing the old window tint. The sun helps soften the glue up with warmth for easier removal.
Pour ammonia in a spray bottle and squirt the remaining window tint adhesive with it. Wait 30 seconds for the ammonia to penetrate the adhesive.
Scrub the adhesive away with a 0000 steel wool pad. Keep an eye out near the corners and edges of the window as well. After successfully removing the window tint glue, wipe the area with several paper towels.
Clean the windows with a general window cleaner. Immediately follow that by drying the windows with paper towels. This will restore a streak-free appearance.