I just posted this on another forum, and hope you can find it useful as well:
Ours were pretty badly rusted in areas around the sink. The worst parts were around the handle insets and along the bottom ridge of the doors. First I removed the cabinet doors (4) and drawers (4), and the hinges (2 hinges could not be removed due to stubborn screws). After washing the pieces, I used a wheel that attaches to a drill to remove paint and rust. The wheel is made by 3M and is black in color, kind of a webby synthetic material, but I'm not sure what it's called. It can be found at Sears or Home Depot. This wheel will remove all rust and paint, so if the pieces are in rough shape, they can be completely reduced to metal. I used sandpaper in areas where the paint was good, just to clean and rough it. For painting, I used Rust-oleum clean metal primer spray paint (2 coats), then a Rust-oleum color spray paint (2 coats), and finished with a clear spray lacquer (2 coats). The cabinet system itself was in good shape, except for the floor area underneath the sink. This was rusted very badly, and completely through around the pipes. I used the sanding wheel on this as well, but did not clean it to bare metal as I didn't want too much dust in the house. I then used Rust-oleum Rust Reformer on all the effected areas, and painted it as above. However, the Rust Reformer requires 3 days drying time before spray-painting.
Anyway, I re-installed all but one door today, and they look fantastic. Email me if you have any questions, or know where to get replacements for those funky hinges they use on the cabinet doors.
PS- Please remember to use a dust mask, or preferably, a respirator, when sanding these cabinets. I don't know what chemicals were used in paint in the '50s, but I'm sure they weren't good.