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With use and the passage of time, silverware can darken due to a chemical reaction between the metal and sulfur compounds present in the environment.
To remove those stains, the United States Environmental Protection Agency (EPA) includes a homemade cleaning method in its guide on Household Hazardous Waste.
The procedure consists of boiling water with salt, baking soda, and aluminum foil. Once the solution is prepared, the silverware is immersed and kept in contact with the mixture for a few minutes to help remove the dark layer and restore its shine.
The method works through an electrochemical reaction in which the aluminum promotes the transformation of the compound responsible for the silver’s darkening.
Unlike abrasive polishes, this technique does not require rubbing the metal surface directly. However, it is not suitable for all pieces: before applying it, it is advisable to know the characteristics of each object and the necessary precautions to avoid damage to its finishes.
What is boiling water with salt, baking soda, and aluminum foil used for?
The combination is used to clean tarnish from silverware, that is, the dark layer that appears on its surface over time.
This phenomenon usually occurs when silver reacts with sulfur compounds present in the environment and forms silver sulfide, a substance that gives the metal its blackened appearance.
The method makes it possible to treat that darkening without relying exclusively on commercial polishing products. To do this, it combines water, salt, baking soda, and aluminum in the same container so that the ingredients promote a reaction capable of reducing the dark layer.
How to clean silverware with boiling water and aluminum foil
The EPA details a simple procedure that can be carried out with common household ingredients. To follow its instructions, you must prepare the mixture and respect the exposure time of the silverware.
- Pour between two and three inches of water -approximately between 5 and 7.5 centimeters- into a shallow pan.
- Add a teaspoon of salt and a teaspoon of baking soda.
- Add a sheet of aluminum foil.
- Bring the water to a boil.
- Fully submerge the silver items and keep them boiling for two to three minutes.
- Carefully remove the silverware and wipe away the tarnish with a cloth.
- Repeat the procedure if dark stains still remain.
During preparation, it is essential to be careful with the boiling water and use suitable utensils to remove the pieces. It is also advisable to check beforehand that the silverware is suitable for this type of treatment, especially if it has handles made of other materials, glued parts, or delicate decorations.
What chemical reaction occurs when boiling silver with baking soda, salt, and aluminum foil
The basis of the method is an electrochemical reaction that makes it possible to reverse part of the process responsible for the darkening of silver. When the metal comes into contact with sulfur compounds present in the environment, silver sulfide (Ag₂S) can form, depositing on the surface and giving it its dark appearance.
By introducing the silver and the aluminum into a hot solution with salt and baking soda, the exchange of electrons between both metals is favored.
Aluminum oxidizes, that is, loses electrons, while the silver present in the sulfide can be reduced and return to its metallic form. The sulfur passes to other chemical species during the process.
The salt and baking soda help the water conduct ions, which facilitates the development of the reaction. The heat, for its part, helps speed up the process.