Copper is a great pure metal, you can do so much with it! It will tarnish though if left in its natural state. It might even grow patina, if you leave it in a moist environment with high humidity. Hey, it turned green like the Statue of Liberty! These are also some of the most wished for qualities about copper. People have tried (and succeeded) over centuries to create various natural patinas and surface effects to make beautiful things with the metal.
These copper cleaning methods are for copper that has not been coated with anything permanent, we are talking just regular oxidation and tarnish over pure copper. If you have a piece of jewelry it might have a type of a “clear coat” on it that was applied to preserve the surface (for example, your piece has patina, or was flame painted or just coated to preserve the natural tone of copper). If this is the case the clear coat needs to be removed first. Often, it can be taken off just by regular sand paper, or sometimes a solvent is needed.
One note about any of these methods, they work great but keep in mind to use some common sense. If you have major grease or other sticky substance on your copper, you need to get those off first. We are talking about cleaning a relatively non greasy piece of metal, if you have a piece of copper you found in the garage under several layers of rubble from 40 years ago…you will probably need something stronger for that!
I just accidentally found your site on the internet and I want to thank you for the many tips about copper, etc. I am just learning how to paint on copper. Best regards, Connie Tyler