I can say it's not necessarily vaping (or smoking) that causes the film (sometimes). I once had a car (2000 Mazda 626) that got an awful film on the windows no matter what I did. The car was never smoked in before I bought it, and I rarely if ever smoked in it (maybe once or twice in the 1 1/2 years I owned it) and about every month I had to clean the windows because there was a nasty cloudy film on them. I cleaned the windows with several different products, and the result was the same, they looked good for a week or so and the film started building up. I didn't vape then, so there was no reason for the windows to be filmy. It was a beautiful car but ended up having major problems with the engine, so got rid of it. Have never had the same problem before or since. I've started seeing a film on the windows in my current car, but I'm sure that is from vaping. Whatever, I'll clean them eventually. I rarely open the windows while vaping so I can understand it building up somewhere.