How to Clean Silver with Homemade Tarnish Remover
Tarnished Silver: Why it Happens
Silver is elegant and beautiful, but it also has a rather unsightly problem: tarnish. Silver tarnishes because it reacts with sulfur in the atmosphere and forms a compound called silver sulfide. Silver sulfide is black, and is the ugly coating that develops over time on silver jewelry, dishes, and silverware. To prevent this problem, some silver items are coated with a very thin layer of another metal (often rhodium) to prevent the natural oxidation process that occurs when silver meets sulfur in the air.
The official chemical process for creating silver tarnish is:
H2S + 2Ag --> Ag2S + H2
Hydrogen sulfide gas makes contact with silver, creating the silver sulfide tarnish and hydrogen gas.
A Cheap and Effective Way to Clean Silver
Removing Silver Tarnish: Better Living Through Chemistry
There are technically two ways to remove silver sulfide from silver objects. The first is through physical force - while this may be effective, it often damages the silver item and leaves ugly scratches on the surface.
A better method is to use chemistry to remove the silver sulfide from the object in question. Since the silver is oxidized, you need a reducing agent to return the blackened silver sulfide to shiny, metallic silver. Aluminum is a wonderful reducing agent, and comes in the convenient (and affordable) form of aluminum foil. For those interested in the chemical reaction, the process is:
3Ag2S + 2Al --> 6Ag + Al2S3
Silver sulfide + aluminum reacts to form silver + aluminum sulfide.
Unfortunately, you cannot simply place a silver item on top of aluminum foil and add hot water to start the reduction process - another agent is needed to help the chemical reaction along.
Since aluminum foil is coated with aluminum hydroxide, sodium bicarbonate is require to eliminate the film, so that the aluminum metal is exposed. Adding the sodium bicarbonate to the water also ionizes the solution, which helps to speed the reduction process.
Cleaning Silver with Foil and Baking Soda
Cleaning Silver: The Basic Steps
Cleaning silver requires a few items:
- Inert basin or bowl (i.e. a plastic or glass container or sink)
- Aluminum foil
- Sodium bicarbonate (also known as baking soda)
- Boiling water
Add about a gallon of boiling (or very hot) water to the inert basin. In the video above, I used our plastic kitchen sink. Use plastic or glass as the reaction vessel: if you have a stainless steel sink, find another place to do your silver cleaning.
Add one cup of baking soda to the hot water solution and stir until dissolved. Place a sheet of aluminum foil at the bottom of the sink. Place the silver object in the sink and wait for a few minutes as the tarnish begins to disappear.
For very heavily tarnished items, the process may need to be repeated more than once. When the silver object is removed from the hot water bath, simply wipe the item with a dry, soft cloth. This will help to wipe off any excess tarnish sitting on the surface of the object.
In the video above, the bowls were extremely tarnished and took two "baths" in the sodium bicarbonate/aluminum foil solution. After wiping with a dry cloth, the bowls were returned to a shiny, silver state.
A Few Cautionary Notes
- Removing silver tarnish will eliminate the silver sulfide (black film) that develops on all silver objects, but it will not remove dirt or oil from the item. Wash your silver prior to removing the tarnish to get the best results.
- The aluminum foil/baking soda method works very well with silver. The higher the purity of the silver, the better the results will be. Unfortunately, this method does not work well with tarnished brass or copper - other methods are required for cleaning those oxidized metals.
- For highly valued silver coins, contact a professional prior to performing any cleaning: you do not want to devalue a rare coin by cleaning it the wrong way (or by cleaning it at all)! For very high-value items, let a professional do the work!