Are you concerned about corrosion or appearance? If the humidity is high enough for corrosion to be a concern, you have other problems too. If humidity is within reasonable levels, the corrosion of the steel should not be a problem.

Wire brush the rust away and paint with Rustoleum or similar rust inhibiting paint.

It's for appearance. Thank you both for your suggestions.

I wouldn't use rustoleum. It's more important what you prime it with than what you finish it with. Using a rusty metal primer will let you finish it with anything.