And this is why your northern car is covered in rust after a few years on the road... you're literally driving through liquid brine for a good 25% of the year.
I am surprised I have any car left to rust thinking of it that way.
I spent 2 months in Foster City during the lockdown at a gig, stuck in a hotel room, driving to a large empty building to do firmware porting on a bench.
One morning I walk out fiddling with my keys, went around the back of my truck and saw a pile of pipes behind it. Wha?
It was the pickup truck parked 2 stalls down from me. Burned during the night. Utterly consumed. No rubber on the rims; just naked metal. The seats were just springs. The license plate a melted blob. The engine on the ground. Broken in half, the cab tilted forward at a crazy angle, the bed tilted back.
Sucks to be that guy! I thought. Then turned to my truck. The left side was melted like a Dali painting, the mirror drooping down, the running boards spilling onto the pavement in strings and puddles. The lights were foamed-up weird sculptures sticking out like alien apendages.
Anyway 6 months later all the parts had arrived and it was repaired and I went back out to drive it home. My baby!
So now I drive a truck that's new on the left side, but a rusted Iowa clunker on the right side. Works for me; I get in the left side so I see that.
Still not feeling the love, California.
What can be done commercially for rusted stuff (cars and such) is to apply rust converters that convert the iron oxide layer on the outside into a stable primer so it seals the outside of the metal from oxidizing further.
Molar mass of Rust Fe2O3 =159.7 g/mol
Rust weighs in around 3x more than bare metal, so that makes this primer one expensive fuel guzzling choice.