Half fill a clean bucket with warm water and then add an appropriate quantity of mild detergent to the bucket. Agitate the contents of the bucket in order to prepare a soapy mixture.
You will now have to get rid of dirt and grime from the wheels. This can take some effort as well as time, especially if this is the first time you are cleaning the wheels since you bought them. Use old rags in tandem with the soapy mixture from the previous step for cleaning dirt and grime. Replace a rag that becomes very dirty with a clean one.
Start vigorously sanding the wheel with 400-600 grit wet/dry sandpaper and continue until pitting on the wheel has been completely removed. You might be tempted to use a power tool to make this step easier. However, that is not a good idea because people who use power tools tend to overdo it. Keep in mind that you might have to use several pieces of 400-600 grit wet/dry sandpaper for even the mildest cases of pitting.
When you have eventually removed the oxidation layer from the wheels, smooth them out with fine grit paper. Your aim should be to remove grooves that might have been left behind.
Use a piece of microfiber cloth to clean leftover dust particles from the surface of the wheels.
Finally, secure your work by applying a uniform layer of aluminum protective clear coat to the entire surface of the rims. Be sure to read the instructions manual that came in the protective clear coat package.