How to remove patina from copper sinks
Depending on the style of copper sink you have, you may be wondering how to remove any tarnish or patina that will develop. Copper naturally will form a patina on the outer surface of the metal when it comes in contact with the elements. Typically there are three types of copper sinks.
Lacquered Copper
If your sink was purchased in a particular color, and does not tarnish at all, with the exception of scratches, you likely own a copper sink with a lacquered finish. This means the only reason it is staying that color is because the copper is unable to react with the elements. A scratch, however, will expose that area, and natural copper patina will begin to develop. You may not want to remove this patina. Better yet, let the raw copper under the scratch patina to the near same color as your sink and then put a sealant on it to blend it. If you wanted to remove this patina, it would be a very long process. You would have to strip the entire lacquered, sealant off and with sandpaper.
Rustic Finish
If your sink was hammered and heated over a fire to bring out coppers natural colors, you have what we call a rustic finish. This type of finish is usually not sealed; it has a living finish. The difference is you typically will not get greens patina as easily since the copper was heated and dark rustic colors are so prevalent. To remove this patina, you are looking at a serious project. The rustic copper finish is usually very thick in these types of sinks. Not that you would ever want to, but to remove the patina from this kind of sink would require an electric sander.
Raw Copper
These sinks will arrive at your door in their natural copper form. Once installed, they will begin to patina when they come in contact with food and other elements. Make a copper tarnish remover by using water and a scotch bright pad. Lightly scrub the sink in till you have achieved your desired copper patina.