Brake Dust on Rough Hubcaps
 

I've got some hubcaps in need of help. Here's a link to what they look like

http://hubcapsonwheels.com/images/30...ion_hubcap.jpg

The windows are very rough texture that has orange/brown dust worked in deep for 33 years. Any good suggestions for scrubbing or eating it without damaging the hubcap finish?