Copper is a rich-coloured metal that has warm overtones and yields a handsome patina which develops with time. Unfortunately, sometimes cleaning, metalwork, or other processes can effect or even remove the patina that is already in place, while new copper won't have any finish at all yet. The patina, or tarnish, can be expedited with a few simple measures to bring out the tarnishing process faster than it would occur naturally. That way you can enjoy the beauty of antique copper without losing years in the process.
Rub the copper with a fine scrubbing sponge and kitchen cleaner to remove any surface dirt and grime. Graduate to an extra-fine sponge to give the copper an very smooth surface and to remove any nicks or imperfections.
Rinse the copper clean with water then swab the surface thoroughly with alcohol and a cloth to remove any fingerprints you have left on the metal. Wear gloves from now on when handling the copper to prevent leaving any new fingerprints behind.
Fill a spray bottle with vinegar and apply a light mist over the copper. Leave the vinegar on the copper until it the colour starts to change. Spray more vinegar on the copper if it begins to dry out.
Rinse the copper clean when the tarnish you want is achieved. If the vinegar is not affecting the copper colour or is taking too long, then you can proceed with the next tarnishing procedure.
Mix one part rapid fixer with two parts water to prepare the tarnishing solution. Pour the solution into a container that can comfortably hold the copper you are working with then immerse the copper in the container.
Agitate the container to keep the solution moving around the copper. Once the water starts to colour, you can leave the copper for 10 minutes to tarnish. If the water becomes so coloured that you can't see through it, remove the copper earlier than 10 minutes.
Take the copper out of the container and rinse it with clean water to remove any traces of fixer. Buff the copper dry with towel to prevent streaks from forming on the surface.
Test an inconspicuous area of the copper piece before tarnishing the entire thing to ensure there are no adverse effects on the metal. Remove some of the tarnish with sandpaper if the colour is too dark for your liking.
Never use abrasive or sharp tools on copper or you will scratch it irreparably.