I am having the toughest time trying to identify the solution to an issue we are having at our wash. There is a film that is being left on vehicles that is not as apparent on the body of the vehicle but can be seen pretty clearly on the rear glass of vehicles near the top as well as some of the side glass. I have swapped out 2 sets of mitter cloths and it "seems" to be better than before but I still see the film on vehicles. I turned down the drying agent and it still seems to be there. Any ideas on how to diagnose this issue?