To polish up copper pots and statues I use lemon and salt. Take the lemon cut in half and sprinkle salt on to it and scrub the bottoms of your pans they are like new afterwards and I like mine so much that I keep them hanging in my kitchen for easy grabbing and also a decorative touch. This works on any copper.
I inherited a small copper "tub" that was stored in a barn. It has turned completely black. What is the best way to restore it's copper finish? Also, once it's cleaned, is there anything that can be put on the surface to keep the copper from getting dull?