Home >> Collecting >> Coin Collecting

How to Detect Cleaned Copper Coins

Harsh cleaning of raw copper coins can leave them with a completely unnatural appearance and diminish their value. When you send coins to grading services, they will not certify them if they have been cleaned. If you want to purchase a raw copper coin as a collector or trader, it is very important to know whether it has been cleaned. Knowing what to look for enables you to identify cleaned copper coins, and it prevents you from becoming a victim of possible fraud.

Instructions

- 1
  Check for factors described in subsequent steps while looking at the copper coins you are interested in. If the coin is available to you only in the form of photographs, observing these factors can be difficult. Ask the seller to send clear photos of the coin. If the seller is hesitant, does not respond to your email requests for such photographs, or sends inadequate photos and says they are the best he could shoot, drop the seller.
- 2
  Examine the copper coin. If it has a very unnatural orange color, it has been cleaned. Copper coins are dipped either to get rid of surface grime or to remove irregular surface toning. If you have encountered copper coins with a blotchy surface of different colors, that is toning. Toning happens when you expose reactive metals to the environment, and copper is one of the most reactive metals. Toning marks cannot be removed from copper coins without leaving a harsh, unnatural orange color on the surface.
- 3
  See whether the copper coin has a mirror-smooth finish. Check for the presence of fine unnatural lines on the surface. These lines might be on just a small spot. If you find these on the coin, it might have been polished by a jeweler's tool, steel wool or a fine-wire brush.
  
  A cleaned copper coin reveals itself with a surface that has a pale-orange shade and might be grainy. Coin images shot at specific angles could conceal such cleaning marks, or they could be manipulated using photo-editing software to mask evidence of cleaning.
  
  If you find the image too real to believe, just question the seller and ask for more photographs from different angles. Compare the coin with a graded coin to identify the unnatural differences.

Coin Collecting