This has probably been done to death... Old wives tales and the motor car vs modern remedies. Lately I have been having slight issues with streeks and smearing of rain and water on the windscreen. I've tried cleaning the screen with household glass cleaner and then repolishing with autoglym glass polish and to be fair it works ok for abit, the it's back to streaking. I know I can clean the screen with white vinegar, didn't have any so used the malt stuff I had. And by eck did it make a difference, more so than other cleaners. So what other old wives tales etc have you guys and gals used on your cars that worked better than modern chemicals or vice versa?