I recently bought a set of Sport Design 19" from ebay and two of the wheels at the back have these black tar liked and brownish stuffs. I have tried WD40 and some wheel cleaning solvent and no luck. Anyone knows what they are and how to clean them?
The best way to remove that stuff, which is the protectant Porsche uses for shipping, is liquid paint polish. Takes it right off. Griots Machine Polishes (used by hand) work great, as so various Maguiars Polishes (like Fine Cut, etc.), Chemical Guys Ultrafine Polish... you get the picture. I use whatever I have laying around on a shelf and it works great. Apply it with a 3" foam pad or a damp cotton towel, and that stuff is easily removed.
Uh, the 2 piles of black stuff look like tar which should be easy enough to be removed with the above methods or just tar remover. But the brown large circular area, cosmoline? To my computer screen, it looks like a hack job trying to remove a tape weight. Yes-no?
It took me few hours today to clean the wheels and the dirty stuff are finally gone.
The black tar I used tar remover with a plastic scrapper to remove them. They did require some effort to take them all out. The brownish stuff I used wheel cleaner and a kitchen scrubber sponge to get them off.
Mineral spirits and a soft rag works very well at getting the tar off. It doesn't even require much effort. Just be sure to wax the wheel when done because the spirits will strip the wax. A good coat of wax, I use Wheel Wax, will also make the wheels much easier to clean in the future.