The real answer is my car stays dirty and unwashed for 4-5 months. You wouldn't watch to chance using a waterless wash with that much dirt and salt, scratching the paint etc. I tell myself that I would bring it over to a DIY touchless car wash bay a few times over the winter, but I haven't done that in years. When you car never sees temperatures above freezing for weeks at a time, it is best to just leave it dirty.