How do I clean the inside of my car’s windows and how do I prevent the film from keep coming back
A film on the windshield is usually caused by material outgassing or a leaking heater core. Did this just start or have you had this problem for some time.
+1
However, with a car that is at least 6 years old, outgassing is not likely to continue to be a problem. My best guess is a leaking heater core, or–even more likely–the OP may be one of those people who keeps his heater set on “recirculate”. During the winter, that is sure to result in fogging of the windows and exacerbating the deposition of a film on the inside of the glass.
Outgassing from the dashboard doesn’t stop, but will abate over time. I still got a windshield film in my 2005 Accord when I sold it 12 years later, same thing for my Silhouette 14 years after we bought it. I didn’t have to clean them as often, of course.