Since I'm on well water that leaves mineral spots, I never wash my truck at home. BUT, if I know a big rain storm is coming I'll take a wet towel with dish soap and soap up the entire truck. Once the rain has passed it's totally clean, dry and spot free.
i would NEVER EVER use a pressure washer ot steam cleaner on any
paint...unless i was TRYING to strip it off the metal !
nothing beats elbow grease...soap and water...LOTS of water...
and rinse the sponge or wash mit OFTEN while youre washing.
You'd have to have a pretty crappy paint job (MAACO, perhaps) to strip paint off of a body with a pressure washer or a steam cleaner. We have a pressure washer here that we use all the time that has never peeled paint off of a vehicle, and I've never seen a car wash that didn't have a pressure washer. My dad's even steam-cleaned his truck pretty hard because he gets vegetable oil all over it, with no problems, except even that didn't get much of the oil off. I guess that free fuel has to have some kind of drawback