The film on the inside of your windshield is off-gassing from plastics plus moisture. Clean it with glass cleaner and two towels, and replace your cabin filter if it's old.
Where the film comes from
- Plastics and vinyl releasing oils in the heat
- Smoke
- Moisture and humidity
- A clogged cabin air filter
Cleaning it properly
- Use an automotive glass cleaner
- Wipe with one microfiber, buff with a dry one
- Reach the base of the windshield with a reach tool or wrapped towel
Keeping it clear
Run the A/C to dehumidify, keep interior surfaces clean, and swap the cabin filter yearly.