LOL! Then there's those of us who simply don't bother. Our vehicles are exposed to salt about 4 months/year - the spring rains rinse the underneath off nicely in April.
I use "Rust Reformer" on any emerging rust; and spray moving parts liberally with silicone spray.
Road salt isn't the only "eater of metal" - I've been reading about communities using "fracking brine" to keep dust down on gravel roads. It makes sense - it's a waste product that's mostly water with a bit of petroleum product mixed in - but it can also contain acids :-( I let a friend borrow my utility trailer to haul a bunch of kayaks to the upper part of Michigan last summer. Every place where mud splashed on the trailer (as they drove the backroads getting to rivers), it left behind a spot of rust! That trailer gets hauled through salt all winter and has never had that happen!