Window tint is plastic film with an adhesive backing that sticks to the inside of a vehicle's windows. In the car, it's used for privacy and to help reflect the sun's heat, glare and UV rays. Over time, the glue begins to dry out and the plastic film fades and bubbles. When this happens, it's time to remove and replace the tint. Getting the old glue off is a time consuming, tedious task, but a necessary one to avoid compromising your view out of the window.
Mix 236ml. water, 113gr. ammonia and 1 tsp dish soap and shake them together in a spray bottle.
Place towels on the car's floor and below the window to be treated. Spray the window with the ammonia solution.
Tape a trash bag over the window to seal the solution in. Leave the solution to soak in and soften the glue for two to four hours or overnight.
Remove the trash bag and spray more ammonia solution onto the window while scraping the softened glue with a razor blade. As you scrape, the glue will turn to a milky solution that can be wiped off with a rag. If you're working on the rear window, just use the ammonia spray and a rag; a razor could easily damage the window's defroster elements.
Work with the car doors open as the ammonia solution has a strong smell.