2008 Gt/cs Wheels

It looks like either acid or chemical contamination led to that.

First step is going to be using a wheel cleaner that's safe for all wheels with a nylon-bristled wheel brush. Meguiar's is your best bet on the cleaner, you can get the brush at any parts store (or a nylon dish brush from Dollar General if on a budget).

Make sure the wheels are cool and follow the instructions on your cleaner to the letter.

After you're done doing that, dry the wheels and evaevaluate. If the problem is gone, you're good. If it's not gone, but there's no pitting, and those areas still lack luster, you'll need a polishing compound and a buffer (there are videos on youtube on how to use one). If there is pitting, you'll need to get a professional involved either in the form of a powdercoater or a wheel repair specialist to get them perfect, but you may be able to get them to a presentable state by polishing.