Copper is such a beautiful, shiny pinkish-orange metal when it is brand-new. It really creates a focal point in your bath or kitchen. However, copper has a tendency to oxidize in a way that is unique to copper alone. It ends up with a green, patchy layer of patina. If you do not like the patina and you would rather keep the copper's natural color, you are going to have to do all of the following to your copper sinks on a regular basis.
Do Not Use Harsh Cleaning Chemicals on Your Copper Sink
Chemicals you would normally use on any other sink for cleaning cannot be used on copper. In fact, these standard kitchen and bath cleaning chemicals will actually hasten the oxidation process. You will end up with more patina than you bargained for.
Make and Use a Safe Homemade Copper Cleaning Paste
Instead, mix equal parts vinegar, salt, water, and flour to make a special copper cleaning paste. Use a soft-bristled cleaning brush or, if you have the patience for it, a toothbrush to spread this paste all around inside the copper sink. Rub it all around in a circular motion, and then use a soft, damp cloth to remove the paste. Because it is a completely natural cleaner too, it will not cause any toxic fumes or contamination with food or dishes. Use this homemade cleaning paste and approach any time your copper sink needs cleaning.
Buff With Linseed Oil
Linseed oil will restore the shine to your copper sink(s). It, too, is completely natural, so it will not harm you or anyone in your home. The oil acts as a protective layer for the copper, preventing it from food acids and halting or slowing the oxidation process.
The Lacquer Option
Some home and garden websites suggest applying a clear lacquer coat to fully seal the copper against water and wear. You would not do this with any indoor sink since the lacquer is not safe for accidental human consumption. You can, however, use a clear coat lacquer on any copper surfaces or copper gardening sinks outdoors, if you so choose.
Something You Should Consider in Regards to the Green Patina
A lot of people do not like the green patina that forms on copper. However, what you may not know or realize is that the patina actually protects the underlying copper metal from further damage. It is something to consider when you are going out of your way to keep the copper looking new and preserve it.