I stumbled onto a trick to make it easier to polish up the center caps on our 5-spoke steel wheels. All it takes is a trip to the plumbing section with a side trip to the nut and bolt department. After body working any dents and dings, now you can comfortably sand with increasingly fine grits, just like color sanding. Use the palm of your hand for the face, and fingers for the side. Factory caps are stainless, not chrome, so have no fear. Put a pan of water on the drill table and wet sand, even. Oh... maybe put some tape around the tangs on the back of the center cap so they can't grab your polishing cloth (or your skin). When you are done they may look so good you are forced to paint your wheels (like olstyle!) or get new lug nuts.