Nevr Dull cleans zinc coatings, as well as SS. If the plating is failing, nothing will refurbish it but new plating. You could remove them and have them nickel plated, or buy new SS depending on their condition. If I bought inexpensive spokes, I'd have them nickel plated as a precaution against rust.
So, Chaser, are they dirty or rusted and failing? Some folks use Coca-Cola and tin foil to remove surface rust without damaging the plating. Then use the rest of the Coke with some Jack, and they'll be great!