when visiting friends in Wisconsin ages ago, I saw a big bumper 4 door Nova on jackstands. it was the guys winter vehicle, dents but no visible rust. all summer long, whenever he changed oil, he would dump the old oil in the doors and trunk turn downs. good thing he had a gravel driveway and the EPA didn't catch wind of it.
Learned the trick from my dad, he had a 66 plymouth fury he bought new, it hauled all us kids home from the hospital, it was his daily drive for 25 years, until mom made him get rid of it because it was too ugly. I even drove it some in high school.
It was not very rusty, but the roof where my dad would rest his hand, was wore down to the red primer.