That black SLK looks really sharp
The clear side markers and mod R170 Euro Spec antenna looks real smart on the black 55.
Here's what I do/use to clean the wheels (takes about 20-30 minutes for 4 wheels) each time before washing the car body:
Materials:
1. Old cellulose sponge (hand-me-downs from the kitchen). This way the sponge is well-worn but still useful and has less chance of scratching the wheels.
2. Modified long brush tool used to clean the coils from underneath the refrigerator (available at WalMart, Home Depot, Sears, etc for about USD $6). This tool comes originally with a tapered end that's about 1/2" wide and 4" long, the main body has bristles that are 1.5" wide and are soft enough to not cause any scratches. To modify: remove the black rubber end cap by twisting it off, cut at the junction between the 1.5-inch-wide main body and the narrow o.5-inch-wide tapered end with pair of pliers (easily done as the twisted wire is on the soft side), reinsert the black rubber end cap by twisting. It's important to reinsert the black end cap or you'll have a sharp edge that can damage paintwork. This also prevents the remaining bristles from unraveling and coming off. The modified brush is about 8.5 inches long on the bristle part, not counting the wooden handle (which is another 8 inches long) and should work ok for wheels that are 9" deep.
3. Meguair's Wheel Brightener wheel cleaner D-140 (safe for clear coats, factory painted and chrome wheels, non-acid), diluted 1:4 (as recommended by manufacturer) in a spray bottle that has graduations on its side. I bought a gallon from a car detailer supply place for USD $24. This was 20 Jan 2007. Pix below show that I still have 2/3 left today (17 months). I generally use this every 1-2 weeks before each car wash.
Method:
1. Rinse wheels with gentle spray from garden hose to remove most of the accumulated brake dust.
2. Spray the diluted wheel brightener solution from Meguairs unto the wheel including the inner surface (usually one squirt between each spoke aiming from the center and outward towards the inner horizontal surface). This stuff works great on removing brake dust.
3. Gently agitate with the wet but worn (but still usable) cellulose sponge. I start at the hub and lug nuts, and then on each spoke at the vertical surface, then on the innner horizontal surface (the sponge only cleans the outer 2 or 3 inches of the inner horizontal surface of the wheel). I also use a dripping garden hose (noozle is opened very slightly) on one hand to continuously keep the sponge wet (much like lubricant being slowly poured over something that's being worked on in industrial applications) while doing the agitation.
4. Use the modified brush to clean the rest of the inner horizontal wheel surface by inserting in-between spokes and clean with a gentle to-and-fro and sideways motion, dripping garden hose on one hand and the brush on the other.
5. Rinse the entire wheel with a gentle spray from garden hose once the whole wheel is done.
Each 16-spoke OEM wheel takes about 5-6 minutes.
I also sometimes spray Z-6 gloss enancer (other products will also work) unto a clean cloth and treat the wheels (after they've been dried with compressed air and towel).
Hope the above saves you some time in cleaning the wheels. I think it works well to keep the wheels relatively clean without having to remove the wheels to clean the inner surface.
My apologies for the long post.