Real silver tarnishes over time, causing its surface to dull or discolor. This natural process affects items from fine jewelry to household silverware, diminishing their characteristic shine. Understanding why this happens and how to manage it can help maintain the beauty of silver pieces.
The Chemistry of Silver Tarnish
Silver tarnishes primarily due to a chemical reaction with sulfur-containing compounds in the air. The most common culprit is hydrogen sulfide, a gas often present in trace amounts. When silver comes into contact with hydrogen sulfide, it forms a layer of silver sulfide. This silver sulfide is a black, insoluble compound that coats the metal’s surface, leading to the characteristic dark appearance.
The discoloration can vary, appearing initially as yellow or brown before progressing to red, blue, and eventually black, a result of light interacting with the thin film of silver sulfide on the surface. Hydrogen sulfide originates from various natural sources, such as volcanic gases, hot springs, and the decomposition of organic matter. It can also come from industrial processes or everyday items like certain foods, rubber, and some cosmetics.
Preventing Silver Tarnish
While tarnish is an inevitable process, several measures can significantly slow its development. Proper storage minimizes silver’s exposure to airborne sulfur compounds and moisture. Storing silver in airtight bags or containers, especially those lined with tarnish-resistant fabric, creates a barrier. Adding anti-tarnish strips or silica gel packets to storage areas can further absorb humidity and sulfur gases.
It is beneficial to avoid exposing silver to certain substances and environments. Chlorine, found in swimming pools and some cleaning agents, and sulfur-containing materials like rubber bands or wool, can accelerate tarnishing. Perspiration, cosmetics, and lotions also contain compounds that react with silver, so apply these products before putting on jewelry and remove it before activities that cause sweating. Maintaining a dry environment is also important, as high humidity can speed up the tarnishing rate.
Cleaning Tarnished Silver
Once silver has tarnished, various methods can restore its luster. For light tarnish, a soft polishing cloth designed for silver can gently remove discoloration. Mild soap and warm water can also be used for cleaning silver that is dull or has a filmy appearance.
For more heavily tarnished items, household remedies can be effective. A paste made from baking soda and water can be applied with a soft cloth to gently rub away tarnish. Another method involves using baking soda, hot water, and aluminum foil. This creates an electrochemical reaction where sulfur atoms transfer from the silver sulfide to the aluminum, converting the silver back into metallic silver. This method avoids abrasive scrubbing, which can remove small amounts of silver over time. Avoid abrasive cleaners or harsh chemicals like chlorine bleach, as these can damage the silver or its plating.