hubs

Hey all, I am going to clean and grease my hubs today. They are pretty nasty. Not sure what the part is called, I think its called the speedo drive. Anyway its the part of ths speedo that on the hub. It is filthy. How should I clean this. Can I throw it in a bucket of chemdip? Should I scrub it...

Just wondering if anyone knows of hubs for spoked wheels for the xs400? I know the rims and spokes are readily available. But is there any aftermarket hubs out there, or are there any other options in the way of hubs.....prefarably ones that will acomodate factory disc brakes front and rear:bike: