My first PT I washed with nothing but water. It was black and I thought I'd found the holy grail. I was an idiot. A good car shampoo will lift the dirt, soften it, provide some lubrication so you don't get those swirl marks that my car developed. Second PT ( it was also black but a GT) I used dish soap, not Dawn but Palmolive and the swirls stopped but it still had water marks even after I dried it right away. Then we tried the Zaino wash, Turtle wax wash, a bunch of them until we landed on Meguiars Gold. None of them can hold a candle to Meguiars Gold. My son has gone on to try Turtle wax Ice wash?, Pinnacle products and he always ends up stealing my Meguiars. The B E S T bar none.