Todd Dailey has a nice little how-to up on his blog, showing you how to restore the shine to your iPod nano with a $4 can of Brasso. He has step-by-step pictures and then end results looks so ...

You should feel the abrassiveness of the Brasso on the CD as you are [polishing]. If not, then use a different papertowel. The brasso is removing part of the plastic from the disc not adding to it ...

We were also able to use some Brasso to clean the chassis and the back of our phones without damaging the texture or paint.