Some 2 or more years ago I reported to the Internet of great luck in restoring sheet metal roofing to its pristine shiny metal from aging rust. I found that a application of roof tar, I use BlackJack brand of which the ingredients is simply asphalt, and after it hardens for over a year and pull off the tar leaves bright shiny steel and never a sign of any rust.
So this year I am testing this asphalt roof tar on some very rusty steel weights of 50 lbs used in old times as scale weights.
I suspect no chemist has found out that asphalt tar reduces rusty steel back to pristine steel. And no chemist thus far knows why or how it reduces steel.
But this is an important advance in steel chemistry because the primer coat on all steels that rust should be this asphalt tar layer. Especially bridges over water.
Archimedes Plutonium