When a piece of sterling silver meets sulfur-containing chemicals in the air, a chemical reaction takes place that causes a black residue to build up on the surface. Known as tarnish, it’s actually silver-sulfide, and it takes more chemistry to remove it. Always be conscious of the method you use, as many solutions remove the silver as well as the tarnish. Avoid abrasives and focus on chemical reactions to preserve your sterling and return the pieces back to their natural, glistening beauty.
Most American sterling silver jewelry, tableware and service pieces are classified as 925 meaning they’re 92.5 percent silver and 7.5 percent another alloy, usually copper. Unlike sterling’s more pure cousins that range up to 98 percent silver, 925 is less malleable and more tarnish-resistant than silver of a higher grade. However, tarnish is a constant reminder that sterling silver of all grades is vulnerable to chemicals in the air.
Specially treated silver cloths remove tarnish easily and won’t scratch the silver. It's vital that the cloth is rotated constantly when you're cleaning the piece, so as to avoid putting the tarnish back onto the sterling. A microfiber cloth or any other soft cloth works, as well. Avoid wood-based products such as paper towels or tissues, because they may scratch the surface of the silver. A cotton swab is useful for getting into tight spaces.
Some pieces contain dark crevices that have been allowed to oxidize. This adds to the look of the sterling silver jewelry and tableware design and shouldn’t be over-cleaned and erased.
Many commercial silver cleaners are toxic and cause harmful fumes. They’re also harsh on the silver, removing the patina, some of the silver and any anti-tarnish coating that may have been applied. While it may be shiny and look like new initially, the piece tarnishes more quickly once its defenses have been removed. Check the ingredients on the label and avoid cleansers that contain abrasives and acids.
If the tarnish removal is a small job, make a paste out of baking soda and warm water and apply small dabs sparingly. Use a clean cloth to spread the mixture, and rub gently to remove the tarnish. Finish with a warm bath, and dry using a clean, soft towel.
Revert to chemistry to remove a lot of tarnish. Place a piece of aluminum foil in a baking dish, dull side down. Put the silver on top of the foil in one layer and pour the hot water over it. Add 2 tablespoons each of salt and baking soda, stirring until the granules disappear. The baking soda acts as a conductor during this electrolysis process, and in five to 10 minutes the tarnish will be off the silver. Use tongs to transfer the pieces into a soapy solution for rinsing, and then dry them.
Exposure to air and to direct sunlight increases the buildup of tarnish. Store sterling silver jewelry in airtight plastic bags containing anti-tarnish strips, a lump of charcoal, a packet of silica gel or a piece of chalk to slow the buildup of tarnish. Limit each bag to one piece of jewelry to prevent scratching, and store it with clasps closed. Sterling silver tableware stored in tarnish-resistant fabric protectors helps prevent tarnish buildup.