How to remove edge scratches from iPhone 4?

I bought a 2nd hand iPhone 4 recently. It's really nice and it's white. But what bothering me is it has a lot of scratches on the edges. They are not on the silver antenna place but on white edges of the phone.
I think replacing the housing is my only hope but do you guys know any other easy ways to get rid of these scratches?
Can I get a new housing without buying a new screen and a touch?

Lesson learned, always use cases.