Tarnished sterling silver.
Why does sterling silver oxidize?
Sterling silver is an alloy of silver (92.5%) and copper(7.5%). Silver on its own won’t tarnish easily, but with copper added it will.
The black and brown oxides built up on your sterling silver jewellery are a result of sulfur (H2S). The tarnishing results from the reaction of copper and sulfides. So why add copper in the first place, if its going to turn things black?
Silver is a very soft metal. It is soft in the sense you can scratch it easily, you can bend it easily and it will wear away easily. Adding copper solves these problems , but at the same time makes sterling silver prone to oxidization. That black oxide which makes your favorite pieces unwearable is due to the copper, but unfortunately the copper makes the silver wearable.
Cleaning the oxide away really isn’t that difficult. Returning your favorite pieces of silver jewellery to its original glory is easy.
Cleaning sterling silver in the jewellery workshop.
I normally clean tarnished sterling silver pieces first in an ultrasonic. I remove all soap, skin oil and grime before proceeding to polishing. For silver jewellery this is important and will often save repeating steps.
I might also use a silver dip to remove all the oxidization, from even the most hard to get to places. It is important to thoroughly clean the piece before using a silver dip in order to achieve an even de-oxidization.
Silver Dip is an etching solution, containing sulfuric acid. I would not recommend using it at home. If you do, it should be used with caution.
If a piece of sterling silver jewellery is embossed or filigree, a certain amount of black oxidization may be part of the design. To highlight details and make filigree standout. Using silver dip will remove both the unwanted and wanted oxidization. In the jewellery workshop we reinstate the desired oxidization, after completing the polishing and cleaning process. This is not normally possible for someone cleaning jewellery at home.
Silver Dip will also pit/etch the surface of the silver. Silver Dip converts the oxide from black to white. This means the piece needs polishing after it has been dipped. Again this would be difficult to achieve at home.
Silver Dip is not a cleaner, it is a de-oxidization agent. Silver Dip reverses the oxidization caused by sulfides.
Acid free silver cleaner.
Another silver de-oxidization technique is using hot water with salt and aluminum strips. This is a popular technique recommended on the Web. Again caution should be followed depending on the intended finish of the piece. This technique is often promoted as a cleaning process, but again it is a de-oxidization technique. It doesn’t really clean the jewellery. It is however far safer than Silver Dip.
SILVER DIP WILL DAMAGE MANY GEM STONES, ESPECIALLY PEARLS, OPALS AND TURQUOISE!
Cleaning sterling silver jewellery at home.
At home I would first clean the piece of sterling silver jewellery either in the ultrasonic cleaner using LilyJewels SparkleClean or hand wash using the same. Removing all the built up oils and grime is the most important step.
Then I would dry the piece of jewellery thoroughly.
Using a Sunshine Yellow cloth or a LilyJewels ProPolishing Pad, I would polish the entire surface of the piece. This technique will leave the intended oxidization in place. Details expressed by oxidization will remain. You will return the piece of jewellery to its intended look.
Cleaning rhodium plated sterling silver.
Much of the cubic zirconia set sterling silver jewellery available at the moment has been rhodium plated, just like the diamond set white gold jewellery it is imitating. To restore this type of jewellery to the condition it was in when you purchased it will require the services of a professional jeweller. Using silver dip or even the salt dip will only highlight the wear of the rhodium plating. I would advise washing the piece and buffing with the Sunshine Blue cloth.