What causes small white pin-head spots on windows?

Answer 1: This may be caused by contaminated water. You might also have small dust particles floating around in your shop. You could also be using a towel that is leaving behind small particles on the window. Either way, it’s always a good idea to use clean water and keep your shop as clean as possible. 

Answer 2: You’re probably dealing with specs of dirt in the air. Tape up your felt gaskets and make sure you’re only touching the glass with the film. These white spots may also occur because you are handling the film. Your skin and your fingertips have a certain amount of oil, and this can contaminate surfaces. 

Answer 3: These small white specs can appear with flushing sides. Contaminants can rush back into the window when you’re flushing.