Hi Jock he rubs it down with clean engine oil and a rag, the water doesn't settle at all
I've also heard of guys using steel wool and WD40.
Not sure if a bare metal truck's a good thing,especially here with our climate,sounds like a lot of hard work!
Maybe it's a WWII "left behind."
Good point Tom, the south east of England is/was full of US bases back in the day....
In fact our 'premier' drag strip is an old US air base,now known as Santa Pod.