I'm going with Steven on this one. If the rust is only on the surface and has not had the chance to progress very far, sanding and refinishing should be fine. However, it will be important that all existing rust be removed before any new primers or paints are applied.
I think it would be worth figuring out why the rust happened (aside from the plumbing or roof leak that supplied the water) in the first place. The presence of rust indicates that water was able to permeate the surface coating. That would suggest that the coating was compromised either by cutting/scraping (perhaps if hard, heavy objects have been slid on and off of them repeatedly) or by standing water migrating through the surface coating (which can happen if the coating is thin and is not a baked on enamel or powder coating). If physical cutting/scraping has taken place, you may want to get some kind of protective material installed on top of the shelves, so that continued use doesn't end up compromising the surface again. 1/8 - inch nylon or acrylic sheet might make a good choice, as these are smooth and durable. Of course, this modification should be weighed against the cost of replacement shelves.
Good luck, and I hope that no archival film was damaged!
Michael
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Michael Holland
Principal/Owner
Michael Holland Productions
Bozeman MT
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