After reading the article on Lifehacker about giving your iPhone a "brushed metal" makeover, I decided to try it myself. Now, I had previously done this same technique back when I had an iPod Photo, and it worked quite well (especially since I bought it off a friend, so it already had some wear to begin with). After getting some materials together, I was ready to start my brushing adventure!
If you look at the photo below, you can see the amount of damage the bezel has endured.
To get rid of this is quite easy; it's just a two step process. First, tape off the plastic backing to avoid additional and unwanted scratches (it's kind of hard to see the tape in the photo).
After that, use a two-sided kitchen sponge (the green/rough side) until you see a smooth, brushed-metal finish. It may take some time to get the look you want, but when you're done, it's well worth it!