What’s the best way to clean a window before tinting?

Answer 1: Tape your seals completely before cleaning. This helps you avoid contamination.    Answer 2: For the back window, you might want to avoid using a blade. Instead, use scrub pads and squeegee spray.    Answer 3: The first step is always to make sure that you’re working in an area without dust. If there is dust in your shop, your windows will become contaminated and there’s really not much you can do about it.