So I don't know what happened or what caused it; been cleaning my wheels at least once a month (or more with the rain lately). But there's some really hard to remove stains on the wheel.... anyone have ideas? I already tried some Meguiers wheel cleaner, car wash soap, and elbow grease to try to get rid of it.

In this picture, inside the red box you'll see the gray stain that looks like its running down the wheel. The other yellowish stain is in the spoke, like yellowish teeth stain, this I've had for a while now. If anyone has ideas on what I could try to remove the gray stain, thanks!

 

Have you tried using a cleaning clay to remove stain? The stain is probally brake dust that got embedded. Try claying. I have used griots garage paint cleaning clay w/speed shine in the past( good results but expensive) and just last week Clay Magic cleaning kit (good results with a $10 savings).
I would then polish & wax to keep your shoes from getting too dirty between cleanings. I will be polishing my s-lites for winter driving tomorrow. It gets too cold in upstate NY to properly detail a car in the winter.

Hope this advise helps.

 

You need to treat your wheel problems just as you would your paint on the body.

It is residual brake dust. To get a really nice looking finish this is likely a two step process. I would take it in two stages. My fist step would be to take a light compound and polish off the brake dust which has attached itself to the surface. From the photo it looks very light and should come off easily. If the area nearest the inside of the wheel is, indeed heavier and more embedded, then a rub with a clay bar and lube like bonz suggested is in order. (here is a how-to)

I also agree with bonz that waxing your wheels inside and out is the way to go. But don't just use any ond carnauba. Use a heat resistant polymer sealant that will last. Klasse, a great sealant that will last months on your paint, is one example.

Finally, you can do what I did and get yourself some EBC Green or Ferodo brake bads which put out about 10% of the dust the stock pads do and stop better as well!

 

I had the same problem on my white wheels, one of our club members owns an auto detailing business and I asked him to take a look. As BradB mentioned it will probably take a light compound to remove the stains. In my case, clay or compounds like ScratchX wouldn't touch the stains. My friend experimented with the various compounds he keeps on his truck and Meguiars #83 Dual Action Cleaner/Polish worked the best. As BradB says, follow this with a good heat resistant polymer sealant and the problem should not return

 

From the picture, it looks like these stains were caused by brake dust dripping from the back of the wheel, around the spokes and down the front of the wheel (after driving in the rain). It may be time to take the tires off and wash inside them very well. You might get by with a careful scrubbing using a foam bottle brush or equivalent but, if you have the jack and space, it will probably be easier to pop the wheels off and clean them thoroughly inside and out. They will also be easier to compound, clay and seal (Klasse or Zaino) while off the car.