Breadboards are meant more for prototyping purposes and aren't really meant to be used in wet / moist / corrosive environments. I'd bet the contacts would probably also corrode if used for any extended duration in such an environment. Well, these types are, at any rate: http://en.wikipedia.org/wiki/Breadboard
Most staples will rust, but as long as it's dry, they should be conductive enough to make connections on a breadboard. Solid stranded copper hookup wire would probably be better, but then you'd need to cut and strip the ends.
Thanks for the response but the question was about the electro-chemistry between the staple and the metal in the breadboard. You know how computer peripheral cards have gold contacts to prevent this. I'm thinking the 2 metals might react and cause damage to the board.
The hookup wire is probably cheaper and easier to work with anyway, and afaik it has no corrosion issues :P
Depends what the staples and the breadboard is made from, I suppose.