I go to coin operated hand spray washes but I don't use the soap or the brush. I just put it on rinse mode to blast away the muck. After I blast all the muck off, I wash it at home in my garage with Optimim No Rinse car wash. Here is a thread about this:
http://www.f30post.com/forums/showthread.php?t=786764
And here is where you can order it as well as other detailing supplies:
http://www.eshine.ca/