Although abrasive products are often advertised on TV or in stores as effective for cleaning coins, this is not the case. Acidic cleaners remove some of the material of the coin’s surface during the process of cleaning it. Although this will make the coin look cleaner and improve its shine, the coin will be damaged and its value diminished.Similarly, you should never scrub or scrape coins in order to remove tarnish or blackness. Products like steel wool or wire brushes will irreversibly damage your coins and remove their value.
 To clean your coins without risking damage to the surface and a reduction of value, you should use only water. Grasp a coin by the edges, and hold it under a gentle stream of lukewarm distilled water. Flip the coin over so that the reverse side is also wet. Then, gently pat the coin dry with a soft cotton towel. This will remove some superficial dirt without scratching the coin.If you live in a city, the tap water will be treated with chlorine. This chemical will discolor the face of your coin. To avoid this, either purchase distilled water from your supermarket, or clean coins under water from a purifier.
 If the distilled water was too weak to effectively clean the surface of a dirty or encrusted coin, the only other non-damaging option is to use a weak soap solution. Pour a small amount of a weak liquid soap into a large bowl, and then fill the bowl with tepid distilled water. Grasp your coin by the edges, and swirl it around in the soap solution. Then rinse the coin under distilled water and pat dry with a clean cloth.Do not use dish detergent to clean your coins; it’s too powerful and abrasive. Instead, use a weak, gentle soap, such as hand soap.
Never clean coins with abrasives or acids.
Clean old coins with water.
Clean old coins in a weak soap solution.
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