I agree that the mr clean car wash thing does work. My experience with it is that the filter can last about 10 car washes or more depending on your mineral content in your water. My only problem is that I only get about 3-4 car washes out of a bottle of soap. (I have 3 SUV's) There is only one other complaint I have about the thing and that is it doesn't really seem to work all that well with highly rainx'd windows. The windows just seem to dry with a ton of spots.