How to Clean Silver – Remove Tarnish Using Chemistry

Exposure to air pollution, water, and other chemicals tarnishes silver. Here is how to clean silver and remove the black tarnish layer using chemistry. All you need are common chemicals and you can polish silverware, jewelry, and other items at home without damaging the precious metal.

What Is Tarnish? Chemical Composition

Tarnish is the name of the black layer that forms on silver. Pure silver or fine silver actually resists tarnish. Sulfur compounds in air or water combine with silver and form black silver sulfide (Ag₂S). While unsightly, the black layer actually protects the underlying metal from attack. Silver sulfide does not dissolve in water or most solvents, but you can remove it with weak acids or using an electrochemical reaction.

However, most silver item consist of sterling silver. Sterling silver is a silver alloy that is 92.5% silver and 7.5% other metals. Usually, the other metal is copper. Sterling silver tarnishes a bit differently from fine silver because of the copper. Copper reacts with oxygen (oxides), sulfur (sulfides and sulfates), and hydrogen, forming a variety of tarnish colors that are collectively called a patina. The methods of cleaning fine silver don’t always work with sterling silver. Some chemicals that clean pure silver react with copper and make the situation worse!

How to Clean Silver at Home Safely

Here are seven methods of cleaning silver at home. The method you choose depends on the type of silver item you are cleaning and the materials you have on hand.

Silver Polishing Dip

The fastest and easiest way of cleaning silver is also non-destructive. Also, you can clean multiple items at once. Homemade silver polishing dip applies electrochemistry. Basically, a redox reaction occurs that removes the sulfur from the tarnish and deposits it onto aluminum foil. The silver remains intact.

1. Line the bottom of a nonmetal bowl with a sheet of aluminum foil.
2. Sprinkle either baking soda (sodium bicarbonate) or washing soda (sodium carbonate) into the bowl.
3. Place the tarnished silver item into the bowl. It needs to touch the aluminum metal.
4. Pour hot water into the bowl so it completely submerges the silver.

The chemical reaction removes tarnish within a couple of minutes. Afterwards, rinse the silver items with clean water and dry them. If discoloration remains, you can repeat the process. However, this usually means you have another tarnish chemical present and need to polish the silver further using a second method.

Caution: The method requires you immerse the silver item in the liquid and place it so it’s touching the silver. So, there is a slight risk of the aluminum scratching the silver. Items that also contain wood, gemstones, or other porous materials may suffer from immersion in hot liquid. Finally, items with a manufacturer patina (intentional dark areas that show the design) will lose the patina and become pure silver-colored.

Lemon Juice and Salt Silver Polish

The weak acid in lemon juice (mostly citric acid) attacks both silver sulfide and copper oxidation products. Meanwhile, the salt gently polishes the metal. This method works well for both solid silver and silver-plated items.

1. Squeeze the juice from one lemon into a bowl.
2. Add three tablespoons of salt. The measurement does not need to be exact.
3. Place the silver items into the bowl and add enough water so that it covers the silver.
4. Let the silver remain in the lemon and salt bath for 5 minutes.

Now, remove the items and rub them with a cellulose sponge or soft cotton cloth. After cleaning the silver, rinse away the lemon and salt using water and dry your items.

Caution: While fairly gentle, undissolved salt can slightly scratch metal. Don’t use this method with plated items where the plating is damaged because the acid will attack exposed underlying metal.

Clean Silver Using Ketchup

Ketchup, tomato sauce, and salsa work as silver cleaning agents. Here again, the weak acid breaks up the tarnish and cleans the metal.

1. Apply ketchup to silver.
2. Using a cellulose (soft) sponge or cotton towel, polish the silver.
3. Rinse completely with warm water and dry the silver.

Caution: There’s no risk of scratching the silver, but once again, use caution when cleaning plated items if the plating shows damage.

Vinegar and Baking Soda Homemade Silver Polish

Baking soda and vinegar react and make sodium acetate, water, and carbon dioxide. Baking soda mixed with water makes a gentle abrasive polish. Vinegar contains acetic acid, which attacks and removes tarnish.

Traditionally, this cleaning method calls for mixing 2 tablespoons of baking soda with 1/2 cup vinegar in a bowl of warm water, soaking the silver, and then rinsing it. While this method loosens tarnish and requires no effort, you’ll get better results if you polish the silver using baking soda and water and then soak it in the bowl with vinegar and warm water. Finally, rinse off the silver and dry it.

Clean Silver Using Laundry Detergent

Laundry detergent is a great all-purpose cleaner. It contains surfactants that lift away particles, leaving a cleaner surface.

1. Mix a bit of detergent into a bowl of warm water.
2. Place the silver into the bowl and let it sit for 5-10 minutes.
3. Rub the items clean using a soft cloth.
4. Rinse the silver using water and dry it.

Caution: Laundry detergent (or any detergent, really) does a good job of cleaning gunk and grime, but does not do much to tarnish. Cleaning off the tarnish requires elbow grease. Only use a soft cloth and expect to put in some effort.

Remove Tarnish Using Hand Sanitizer

Hand sanitizer is a mixture of alcohol and water. It gently removes grime and light tarnish. Rub it into silver using a soft sponge or cotton cloth. Rinse the cleaned silver and dry it.

Caution: Hand sanitizer alone cannot remove significant tarnish. It works best on lightly soiled items.

Using Toothpaste as Silver Polish

Toothpaste contains gentle abrasives that physically scrub away tarnish. Rub toothpaste onto the silver as a polish. Don’t use a gel toothpaste because it won’t contain enough cleaning particles.

Caution: Toothpaste can scratch silver. If you use a toothbrush as a cleaning tool, use the softest brush possible. Even better, use a sponge or soft cloth.

Protect Silver From Tarnish

Once you have shiny, clean silver keep it that way. Wrap individual silver pieces in cotton or acid-free paper so they don’t scratch one another and seal them away from air and moisture in a plastic bag. Before closing the bag, add a piece of chalk or a silica gel packet. Chalk and silica are desiccants. They absorb any moisture already present in the air.

References

• Comey, Arthur Messinger; Hahn, Dorothy A. (1921). A Dictionary of Chemical Solubilities: Inorganic (2nd ed.). New York: The MacMillan Company.
• Kauffman, Henry J. (1995). The Colonial Silversmith: His Techniques & His Products. Mendham, NJ: Astragal. ISBN 978-1879335653.
• Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
• Watt, Susan (2003). “How silver reacts”. Silver. The Elements. Tarrytown, NY: Marshall Cavendish. ISBN 0-7614-1464-9.
• Zumdahl, Steven S.; DeCoste, Donald J. (2013). Chemical Principles (7th ed.). ISBN 978-1-111-58065-0.