You put away a brilliant, shining silver necklace in a drawer, and a few months later, you pull out a dull, blackish-yellow chain. Why does silver do this, and what is the best way to clean it without destroying the metal?
The Chemistry of Tarnish
Tarnish is not dirt; it is a chemical reaction. When silver (especially the copper alloy inside 925 Sterling Silver) is exposed to hydrogen sulfide gas in the air, it reacts to form Silver Sulfide (Ag2S), which is black.
Common culprits that accelerate tarnish include:
- Humidity and sweat.
- Perfumes, lotions, and hairsprays.
- Rubber bands (which contain sulfur).
- Cooking eggs, onions, or mayonnaise nearby.
The Danger of Abrasive Polishes
Most commercial silver polishes (and toothpaste!) contain micro-abrasives. When you rub tarnished silver with these pastes, you are physically scratching off the black Silver Sulfide layer. The problem? You are also scratching off the silver itself.
Over years of aggressive polishing, ornate details on silver coins or vintage jewelry will completely flatten out, and the item will lose weight.
The Scientific, No-Scrub Cleaning Method
You can reverse the chemical reaction using household items. This method breaks the sulfur bond and returns the silver to the item, rather than scrubbing it away.
- Line a glass bowl with aluminum foil (shiny side up).
- Place your tarnished silver items on the foil (they must touch the foil).
- Sprinkle a generous amount of baking soda over the silver.
- Pour boiling water into the bowl until the silver is submerged.
You will smell a faint rotten-egg odor (that is the sulfur leaving the silver) and see the tarnish disappear instantly. The sulfur transfers from the silver to the aluminum foil. Rinse with clean water and dry with a soft microfiber cloth. Your silver is clean, and you haven't lost a milligram of metal!