Maybe at one point a previous owner (assuming you are not original) applied some ZoopSeal to them? Otherwise, you should be able to take a Powerball and (pic your aluminum polish) and go at it.

-Dean

Blue Rooster and I are in the same boat. My wheels (SPO 1862) are clear-coated with dark centers. Apparently the practice of clear-coating aluminum wheels has been dropped in favor of a bare finish.

Does the chroming process work well over aluminum? I seem to remember a problem with the rates of expansion & contraction in the two dissimilar metals....

Joe- I dont know why. I can clean the centers....which is painted gun metal grey, but the outer rim is a different animal. I can polish the water spots and what not off, but the shine is no where near the above pic on the black cobra. Maybe I'll shine em up best I can and take a pic so you can see it.

From a 28-time First Place Concour winner...
 

Yep...I had the "Concours Nut" disease for over 15 years...when I was in Porsche Club of America. I used one of just about every kind of polish and cleaner out there.

I've used RT's Metal Polish as he sells on his website, and indeed, it's a pretty good polish. It contains jewelers rouge and some petroleum distillates and will indeed separate on the shelf. It must be well mixed to maintain a soupy suspension of all the ingredients. And...if you're not careful...the petroleum distillate can evaporate, leaving the polish more of a pasty consistency. It still works well, however, it's best to kep the stuff in suspension and soupy when you use it.

I've just bought a Zoopseal kit...the stuff that you seal polished metal with after you're done polishing it. It supposed to last for two years...so I'll have to let you know about it's durability. Included in the kit is a pint of Zoop's Metal Polish, and it's a really good one, too. I removed my brushed aluminum Olthoff-designed radiator header tank to repair the leaking chromed made-in-Taiwan pot metal water inlet on the intake manifold. While it was all apart, I chucked the header tank mounting bracket in my vise and hand polished the tank using sand paper, RT's Metal Polish, Zoop's Metal Polish, and some Brasso. All worked well, but the Zoop's stuff left a more polished almost chrome-like surface. RT's polish is the most aggressive - but remember some of my petroleum distillate had evaporated.

I first sanded the tank all over with 400 grit wet/dry garnet paper. Then with 800 and finally 2000 grit paper. Final sanding was done with 4000 grit garnet paper and some water-n-dishwashing soap suspension. It was dull looking when I finished, but all the scratches were gone. Polishing with RT's Metal Polish made it look 150% better...then successive polishing with Brasso and finally Zoop's polish did the trick. The Zoopseal sealer went on next...and fiollowing their directions, their Zoop Cleaner finished the process. I'm very pleased with the results...fiigerprints wipe right off...waterspots, too. I'll have to let you know about the durability.

Overall....several hours involved in hand polishing, but I spread it out over several evenings so it wasn't so bad. I'd give RT's Metal Polish a big thumbs up and would buy it again. Same with Zoop's Polish and Brasso, too.

For polishing wheel rims I like RT's Polish, followed by the Zoops Polish. I plan on sealing my wheel rims with Zoopseal before I go to VIR over Memorial Day weekend. I like to jack up the car, too, and just spin the wheel as I polish it it. Works well...besides, my little roll-around stool has a shelf just perfect for my margarita... :p