Brake Dust
PS: If this is supposed to be in wheels, can a mod move it? I didnt really see any wheel appearance threads in there...
use an aluminum polish, you can get it from any auto store. the brake dust has corroded the aluminum, so it wont simply wash off, you need to polish the top layer of aluminum off and since it looks like your wheels are silver, get silver wheel paint and maybe repaint them, or take the time to polish them
But dang, if it really has corroded through the paint, you might want to think about upgrading wheels

That's going to be a major PITA to fix.


