it's great car prep, it's what the pro's use when cleaning up a car, for example a used one that is going to be sold later. Basically they do cars in volume, so they need a quick effective method of car prep before waxing. Car finished accumlate many things over time (the environment is not nice). The acid neutrallizes all the bases and the base neutralizes all the acids, the the finishing rinse makes it all pH balanced. Great prep, sorta like a "chemical" clay, but SMR will be needed for swirls.