I always empty the gears, seals, o-rings and shims out of the diff case and wipte all of them down with paper towels to get the excess diff fluid off. Once I get the bulk of the silicone off I spray them with [link=http://www.southeastrc.com/item/HPI9062]THIS[/link] engine cleaner/degreaser and assist with a toothbrush. After that I spray everything down with WD-40 and wipe everything clean with a few new sheets of paper towel. Then just re-assemble and fill with your diff fluid of choice. It usually takes me about an hour to do all three.

Make sure to put a towel down because that silicone oil has a way of getting everywhere.