Water heater out for repairs - anything else to do?

White stuff is minerals disloved in the water more than likely.

As others have said hose it out.

Replacing the element.. Might as well and keep old one as a spare.

If I were doing that much work.. i'd have 'em put a 2nd element port in and put a standard RV element in one and a 240 element in the other. .That way I'd have HIGH for when I'm on 50 amps or need a quick recovery and a LOW for use on 30 amps and not doing dishes or showering. Leaves more power for other uses.