http://www.peachparts.com/Wikka/LeesDetailingFaq

Works better than anything I have ever done.

If you use a power washer, assuming it is an electric or gasoline type power washer, then whatever is in the water (including sediment and mineral deposits from the last use) and whatever is on the paint (bird droppings, dirt, tree sap) is driven into or across the surface of your paint under pressure. These things can even remove paint.

If you are talking about the water tap powered revolving head washers, the plastic bristles are capable of scratching paint and swirling stuff around.

I would spend the money on premium wash and rinse products, towels, and a Porter Cable buffer. IMHO.

__________________
John

2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)

Click to see 87 300E