[Carl n Susan]

There are a couple of companies in Yuma, AZ who wash and hand wax 40' RVs for $120 (truck is $20 more). They are very popular and do hundreds of rigs each month during the winter season. They all use a pressure washer. Not to clean the RV, brush and soap do that, but to apply water to wet the RV and then rinse after the wash. They use a wide spread tip and it is held way away for the rig.

This is much like you would do at home with a hose. The difference is the water in Yuma contains high concentrations of salt. The vendors there bring a tank of Reverse Osmosis (RO) water which they use, via the pressure washer, as it is mineral free. It drys without spotting and doen't require wiping to dry it.