I used to use that S-100 on the rims of my RK but over time it really F****D them up.. The best thing i found is SIMPLE GREEN you'll be surprised how well it works on hard to get out dirt and grim. They have another one by S.G. called EXTREME AIRCRAFT CLEANER the regular one works perfectly for my needs.It does a great job on guns too.I just replaced both chrome rims on the RK because of using harsh chemicals on them threw the years.
I have used a shark steamer before and it's ok for general cleaning ... But if they are oxidized its a waste of time ...... I use never dull to polish and apply a coat of wax after polishing....