If it isn't too awful bad, a good stiff brush and Flitz on some patches will clean it up.

http://search.yahoo.com/search;_ylt=A0oG7jom61FSUCEARmNXNyoA?ei=UTF-8&fr=yfp-t-138&p=flitz+polish&rs=0&fr2=rs-bottom

You can get it almost any hardware store.

Brew coffee....not tards