After Chrome Removal from aluminum what is the best way to remove remaining copper?

I just recently had some wheels Dechromed. I want to get to the bare aluminum on the lips of the wheels so I can eventually polish them. Sanding by hand is the only way I've tried so far and it is taking FOREVER. The copper coat is hard enough to sand through but then there is another metal underneath before the aluminum and that takes forever to sand through.

Hi there in response to your question I understand you have removed the chrome yes but now your trying to remove the Copper theres a really good way to do this without causing any damage to the wheels themselves and if there's still Nickel no problem it removes Nickel also Nitric Acid will remove Nickel And Copper From Aluminum depending on the thickness of the Copper Or Nickel. time to remove will vary on the thickness I hope this helps your question oh and another thing id suggest you do this in a well ventilated area with a respiratory mask as Nitric Acid Is very Toxic and produces a lot of Fumes and Vapours however Nitric Acid Is Also Very Corrosive so please take care when working with Nitric Acid wear protective clothing as well gloves and protective eye wear hope this helps you

Michael Jones Electroplater