How to remove marks from display edge?

I have noticed quite a lot of small abrasion marks around the bezel area at the front screen on my iPhone 4. These small marks are on the front vertical lip directly beside the stainless steel band that goes around the phone and are not on the flat front LCD.

These are small cosmetic marks but as i'm preparing thephone for sale I was wondering if anyone knew what is the best way to remove them? I've tried gently rubbing with a dry cloth but this didn't make anydifference.

Is the material that forms the lip beside the stainless steel band also glass?

Thanks