I use white vinegar and a microfiber cloth to ensure I don’t tear the film.
Straight white cleaning vinegar and a microfiber cloth.
Deense...Use vinegar and newspaper
If it's the UV solar film you should use sift rags and an ammonia free window cleaner. I use Sprayway glass cleaner and a micro cloth on my treated windows. I love Sprayway I use it on everything. Comes in can with a blue lid. It's a foam and works and smells great.
This cleaner works well for glass and other areas exposed to weather: https://amzn.to/2q7ghue
Hope this Helps! Jeremy - https://do-daddy.com
We like to use Norwex window cloths which only need water. I don't sell them, but you can find them at Norwex.com I believe. Good luck!
You might check with the manufacturer of the film to find out how best to clean it as they'll likely have great tips.