Re: Cleaning spokes
I think the spokes are zinc plated or electro-galvanised, rather than true hot-dipped galvanised finish. The zinc is designed to be sacrificial, so it corrodes preferentially, to protect the steel underneath. Problem is, the zinc then pits, and fills with zinc oxide, so it goes dull and gray.
A mild abrasive will clean it up, and polish the surface, but (as with any abrasive) you will remove some of the protective zinc in the process.
Because zinc is quite soft, it will usually polish up with soft wire wool, and this may remove less zinc than an abrasive polish, but like most things, once the corrosion has started, you can never get it back to the original finish. If you want to try the wire wool, use an old Brillo pad on a small area first, to see how it works out. The more pitted the zinc, the less chance you have of achieving a good finish - but you knew that...