As Domestic Bliss says - never, ever a pressure washer. I use a brush (don't know what they are called) I use it on my car, caravan, and even her car (sometimes)

The makers use a mastic and over many years it dries out, stick a pressure washer on it and you blow it away like dirt, the water is forced down the cracks and the caravan is deceased

However - the best bit - you can earn money cleaning static caravans or even just their windows. I knew a bloke who used to charge £30 to wash and polish statics and that was 6 years ago! Plus alot of them have patios to clean! In fact the guy I bought my first wfp set up from used it to clean caravans.
So you don't just have to look at just touring caravans - static sites near towns can have people who use them to live in and that is where the market is
