Film on Windows
When I was a teenager,years ago,I used to hang out at the Chrysler dealership.One of the fellows used to detail new cars,he used Bon Ami soap that came in a bar. He would wet a cloth and make a light paste and rub on the windows,when it dried he took a terry cloth towel and wiped them off.He told meit was some sort of oil that ordinary cleaners would not remove.But his method worked excellant.Only about once a year you had to do this.I also know coke cola will take road film off of a windshield,Ive tried it in the rain,it works no more smears from the wipers.