Humid storage conditions or the passage of time can lead to rust on your bike spokes, particularly if you have an older collector bike with carbon-steel spokes plated with chrome or zinc. More expensive stainless steel spokes should not rust. You can readily clean inexpensive spokes to remove rust.
Rub each spoke with fine or extra-fine steel or brass wool pads. Pinch the steel wool on the spoke and run it the length of the spoke. Rotate the pinched wool around difficult spots. Alternatively, use a scouring pad.
Continue until the spoke is rust free. As the steel wool breaks down while you rub it, move to fresher parts of the pad.
Rub wax over the spoke and wipe off the excess.
Tips
Keep the bike in a dry, covered storage area to deter rust, recommends Terry Meany in “The Complete Idiot’s Guide to Bike Maintenance and Repair.” Or if the bike must stay outside, cover it under a piece of plastic. Replace rusted spoke nipples, as you cannot rub these clean nor use them to adjust spoke tension.