Do spray-on and rinse off cleaners really get the vehicle clean?
It would depend on a couple of factors. How dirty the vehicle is; what kind of dirt; how long the dirt has been on there; how many times you go through the spray-on/rinse-off process, and so forth. Basically, if you have a filthy vehicle and try to get it clean with spray-on/rinse-off cleaners – you’ll be there a very long time, and need gallons of cleaner. Cleaners basically work by attaching themselves to grease and oil (not things like soot or dust), and refusing to attach to water. Hence, you spray the product onto the grime and some of it sticks to the cleaner. You rinse it off, and the stuck grime rinses away. But the cleaner will not burrow down into the grime to get all the layers. And x amount of cleaner will only allow x amount of grime to stick to it. Of course, the agitation created by the stream of water will help some. If your vehicle is really dirty, mix up a generous batch of car wash detergent – lots of water. Lavish it on with sponges, or better yet, soft car washing brushes (horsehair is excellent) on the painted areas, and tougher brushes on the harder or non-visible areas. Use lots of the soapy water and agitation. Wash everywhere twice.
