for grime I use kerosene (sp?).. yes it is bad, I use it on my chains to or put some on a rag to wipe stuff off. I know what you mean about spoke nipples. Some may warn against this but I use steel wool and even sand paper on old spokes.. I have a nice set of vintage wheels (japanese but still nice black hubs and rims) with very corroded spokes I started to clean them and now am thinking to hell with this I'm going to relace them with new black spokes, they'll look way better anyway... I am going to try vinegar though to get old parts shiney again.