Detroit locker

I do have a 489 case (empty) that I purchased at the swap meet, too. Also, Cass (Dr. Diff) advised that it will in fact fit. He says it is a '60's era unit.

What would be the best way to clean up the surface rust?
If it was mine, I'd blow it apart and soak it all in vinegar. They're VERY simple in design. But I don't know what your abilities are, so.......