I go to a touchless down the street from me, just for the undercarriage wash. I take it home and wash it by hand in the garage. Also have a Karcher power washer that I use on wheels after letting Sonax soak for 4 or so minutes. I just bought Optimum No Rinse wash for the first time and still not convinced it does not scratch the surface. It came out great, but I can't see using it with Winter grime and dried salt.