I regularly have my car washed and dried at a local place run by East Europeans. The car always comes out dry and shiny, all hand wash and dried. BUT, in between jet washes they spray on a something from pressure bottles all over bodywork and then pressure wash again. They do not use jet washes in the engine bay, at least not on my car! All for £7 seems a bargain to me, since I can't do it myself for some months yet due to a broken hip. I have asked them what is the spray they use, but the language barrier is too difficult. Does anyone think this spray stuff is doing any harm? I do have a full valet and polish every six months as well. Any comments welcome.