Recently after a snowfall and the roads being treated I noticed all of my black trim on the bumpers, fender trim and lower black panels have been smeared with a white substance that won't come off. I am sure it is from the road salt or snow melting chemical. When I say smeared it is because there is no pattern to the marks. I tried everything to get them off but to no avail. Mothers Back to Black will cover them but when it wears off the marks reappear. I usually clean the car as soon as possible after driving in the salt. Has anyone else experienced this problem?