I've looked at car wash products that you spray on as you dry, but I've never bought one because they all had petroleum products in them. I didn't want to put a greasy film on my clean truck. While visiting Bob last month, he showed me this product that is water based and recommended by his friend that builds show cars. He gave me a sample to try and after using it I must say that I'm impressed with the results. It's always annoying to work hard on a good wash job and then end up with water marks and streaks. This time though, the truck looks great. Just spray this on and wipe with a soft cotton cloth. The car doesn't have to be dry first, but it doesn't matter if it is. It's called "Wash Wax All" and it's available at many aviation maintenance shops, or you can order it online. Use this link to visit the company website.