I have a Rallye edition with the gold rims... The first 600 miles the goop that the factory installs as chain lube pretty much trashed them. I had to clean them after every ride...
I just tried Goo Gone which is a citrus based solvent. I ripped an old terry cloth towel into strips and squares... I used the squares to clean the rims and the strips to clean the spokes.
This leaves and oily residue on the wheels which I am hoping shields the rims and spokes from future build up.
I also cleaned the cast wheels on my wifes 750 with the same product. Her wheels are gray so they looked OK but close examination showed the same residue from the factory chain lube.