If you just want to get it bright and shiny - you can use any copper cleaner, or even Bar Keepers Friend with a little water and a sponge.
If you are wanting to remove the scratches - that is a little more involved. You'll have to remove some of the metal by grinding, buffing and polishing them out - or take it to someone who can do it for you. Here is what is involved: An Introduction to Buffing and Polishing
Copper is a soft metal - so if you're going to actually use the pan to cook in it's just going to get scratched again.