Sorry but it's not oxidation in my opinion.
You got some acid wheel cleaner on their or something just as bad.
What you need to do is remove the clear coat and then the metal polishes can do their job.
Get some Mar-hyde or any brand of spray paint remover and it will remove this layer of clear coat.
Be sure to take your wheels off the car so the spray remover doesn't get on you car.
You can get this stuff at lowe's or Home Depot for about 4 bucks.
I actually did this to my wheels on my 300zx and they look great.
Remember, that once the clear is removed you will have to polish the metal every few months
Metal Madness metal polish is the best metal polish. It beats Mothers ,Semi-chrome Wenol etc. Faster results with out loading you towel or buffing wheel with all that black Gunk. The site is
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