Matthew E. writes: I had some very tarnished coins and I cleaned and polished them and they are now very nice looking. Someone told me that i ruined them by doing this. Why?
Because you removed the original surface. Collectors of art works (and that includes coins) prize originality above all. If you had found a Louis XVI chest of drawers and sanded the finish off and then refinished it with a modern varnish, it might look better to an untrained eye, but you would have removed not only the varnish but about 80% of its value.
Polishing coins is an effort to “restore” a coin to uncirculated condition. Uncirculated coins have “luster”, that is flow lines that are created at the time the coin is struck in the coin press. These radial lines emanate from the center of the coin outward to the rim and reflect the actual flow of metal at the time of striking. As a coin wears, the flow lines, which sit on the very top surface of the coin, are worn away. By the time a coin has been in circulation long enough to create light wear on the design, the flow lines are about gone and so is the luster. Polishing a coin to make it “shiny” doesn’t restore the flow lines that create the optical effect of light traveling around in a circle known as luster. It also doesn’t restore wear on the high points of the design. Cleaning and polishing the coins accomplishes two things:
1. The coin no longer has luster but is shiny. It is also no longer uncirculated.
2. The value of the coin has now slipped from MS6? to G4.
There are situations where coins have been in the ground or the ocean for long periods of time. Restoration of antiquities is a fine art that strives to remove dirt, coral, verdigris and other problems WITHOUT harming the actual surface of the piece.
Generally, coins should be left in their original condition. Wear is certainly acceptable. Very rare and valuable coins with environmental problems can be treated by a professional, not to improve the grade, but to prevent further damage. One such professional is the NGC conservation service.
