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How to Tone a Copper Coin

Coin toning means that a coin is tarnished. Any coins that are not made of gold will start to react to the air the minute that they leave the mint. Over time, these reactions cause the coins to dull, tarnish and change colors. Surprisingly, ancient coins that remain toned have more value to collectors than coins that have been cleaned and shined. There are ways to tone a coin more quickly than the natural process would allow.

Things You'll Need

Household ammonia
Water
Clean glass jar
Cotton swabs
Protective goggles
Breathing mask
Protective gloves

Instructions

- 1
  Prepare a 10 percent ammonia solution using a bottle of regular household ammonia. Mix ten milliliters of ammonia with ninety milliliters of water in a clean glass jar to create the solution.
- 2
  Lay the copper coin on a clean old towel or rag. Wear protective goggles and gloves as well as a breathing mask.
- 3
  Dip a cotton swab into the 10 percent ammonia solution. Lightly blot the cotton swab on the side of the coin that is facing up until the coin has been covered with the ammonia. Wait ten minutes, then turn the coin over and repeat. Continue this process until the coin has darkened.

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