i've been cleaning static caravans for abt 10 yrs now its a good earner, i usually do them on the days iam rained off from window cleaning, started with just a couple of sites now do abt 15 sites within abt 30mile radious, we charge abt £25 per van but was advised by site managers not to touch the roofs to much risk of leaking in so dnt do them we clean the spouts out with a pole with a hook on the end with rubber tubing over it so it dnt damage paint, we then wash with wax shine using car wash brushes then rinse VERY lightly with a pressure washer fed from an IBC tank mounted on a trailer. the sites book me or the owners ring me direct each year,go for it good earner,