Ethan,
I believe one test to see if there is clearcoat left is to go back with a small amount of rubbing compound and polish a small area of the wheel with a white cloth. If you see silver residue on the cloth, it means you've hit paint. If not, you probably still have some clearcoat left.

Maybe they spray a heavier clearcoat on the wheels than on the body?

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Steve
'93 400E

Below is the link for the product called "Wheel Wax". It is specifically formulated for protecting a clean wheel. I'll be trying this on my Brand new 15x7 wheels.

I'm sure this would be at most auto supply stores.

http://www.tirerack.com/accessories/wheelwax/wheelwax.jsp

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Rick

'85 380 SL (sold)
'85 Carrera Flatnose
'71 280 SL Signal Red/Cognac

Ethan,
I just read how you cleaned your wheels.
After using a medium polish I would folow up with a fine/very fine polish. Medium grits will leave a nice bite for dirt and impurities to collect.
Hope this helps.

__________________
Rick

'85 380 SL (sold)
'85 Carrera Flatnose
'71 280 SL Signal Red/Cognac

RickM, that is a very interesting point, I was thinking the metal wheel was so hard only the softer brake dust would be binded and rubbed away by the medium polish. BUt if they use clear coats and paint, then maybe I made the surface rougher and more able for dirt to adhere.

I am going to test for clearcoat, and look to see if dirt is more quickly adhereing to my wheel finish.

No matter which way it goes, before I compounded my wheels they were awful and a few previous applications of P21 wheel cleaner were having no effect.

I appreciate all the responses, and will fine cut polish and check the clearcoat.