It doesn't bother me too much, its just that I hate looking at it. I guess its better than having an ugly case ruining the aesthetic of it. I've seen some iPod metal cleaners at Best Buy. Do those have any hope of cleaning these off?
Have you considered a skin from Invisible Shield or a Best Skins Ever? If the scratches are very light, the application of a skin might actually cover the scratches up, and prevent new ones.
I have a clear plastic backing on the back of my 1st gen, like what most people put on the front screen. It not only shows off the logo but keeps it from being scratched!!
I actually have one from FullBodyFilms, but did a pretty horrible job and now have a bunch of air bubbles. I just get really irritated when the beauty of the product gets ruined by my obsession to keep it beautiful.