What would I need to do it? Just some fine grit sand paper as well as a metal polish or?

I just used sandpaper and a piece of 2"x4" .. Staple the sandpaper to the block of 2x4 to keep it level, then start coarse and work your way down to a finer grit. Once you've reached the desired shine, you can use metal polish and just rub it in.. There are other ways to do it with rouge and wheels, but I've never done it that way.

That's what I was figuring. Just wet sand it and clean it up, I think.

it did come out pretty well

I did the same thing the other day, started with coarse and worked my way down to fine.

I just sanded by hand (without a block of wood etc.) to avoid scratching any other paint. Looks like it wouldn't be a problem with the n/t valve cover but there's a bit more going on with ours.

Still, all it really takes is time. I'm gonna clean the valve cover with spray 9 today and then see how that does

Defiantly pick up some mothers aluminum polish to use after the fine grit. It will remove the fine scratches you can still see, and we all know nicely polished aluminum looks sweet.