I'm not kidding here... but for the 2wd slash, I pulled the electronics... that's it.. left the bearings and everything and threw it in the dishwasher. Then I'd give it a nice coat of wd40 (sometimes).
However, I noticed the plastic got a little softer. After the Dry Cycle, I could twist the chassis like it had the articulation of a rock crawler!
But it looked good!!!!