I would definately agree with the recomendation to get someone to do it who had the propper kit, I got all my suspention blasted and re-painted (enammeled) and it was well woth the 50 pounds or what ever it cost for the rear suspention.
For the diff I used a wire brush in an electric drill, one that is shaped like a paintbrush rather than a disc. This gets between the webbings.
I then laquered it with an aerosol from Halfrauds. it appears to be holding up well, it is not polished - just clean.
Nick