How does one preserve the inside of a driver quality bumper, rusty metal primer?

[Dibbons]

I'm satisfied (for now) with my driver quality rear bumper, but on the inside (where it does not show) it is kind of rusty. Should I just spray some Rust Oleum on there for now? Might straighten it and re-chrome it in the future, might not.

 

[NJRR]

Use the Rustoleum Rust Reformer. It chemically reacts with the rust to prevent more rusting as opposed to just covering it up with paint.

 

[Lionized]

WD-40 or Fluid Film. Whichever's cheapest.