How to remove scratch from iPhone 4 on the side (grey metal thing)?

How to remove scratch from iPhone 4 on the side (grey metal thing)?

Try toothpaste (yes, I'm serious.)

Sorry you can't, you can try buffing it out but that generally does not work

Buff it out

Hi this is a metal case which when scratched might not make it easy to remove a scratch.

If the metal is exposed you must apply paint.
Then you can use body shop rubbing compound to carefully buff it level.
Best is just leave it, and apply wax to reduce corrosion from body oils.