How do I polish brash lamp?

Give plain white toothpaste a try. Use a cloth for the smooth parts and a toothbrush for the decorative parts. It rinses off easily and doesn't leave residue yucky stuff all over that is hard to clean up and smells better, too. It cleans up pretty much all metals.

There are a variety of brass polishes as shown in this link. It still takes elbow grease to polish them, but it works,

https://www.google.com/search?q=brass+polish&ie=utf-8&oe=utf-8&client=firefox-b-1-ab

fine steel wool, rub a small area first, and if it does work ok then do the rest the same way.

Brasso and a soft clothe

I use Brasso. It works better than any DIY product in less time.

I would not use anything except plain white toothpaste in case it is not real brass

thanks!

Ketchup

Put ketchup on it let it sit for 20 minutes then scrub away.