Coin cleaning

Solutions from pencil erasers to wire brushes and potassium cyanide were all used as cleaning agents with the goal to make the coin look brilliant again.

[2] Penny boards were even made with instructions on how collectors should properly clean their coins by using a pencil eraser with a little bit of vinegar.

When submitted examples were finally viewed under the microscope and trained naked eye, the effects of treating coins were revealed to be less than ideal.

Richard Snow, who specializes in the field of Flying Eagle and Indian Head cents, wrote that some cleaning techniques could improve the surface of a coin.

[8] Kenneth Bressett and A. Kosoff also wrote opinions on the matter saying that once a coin has been "stripped" of its original surface and luster, it can "never be fully restored or made Uncirculated again".

[21] While the cleaning process involves desalination in order to remove harmful salts that include chlorides, any potential damage depends on the type of metal the coin was originally minted in.

[22] Sea water is very corrosive and destructive to silver or copper coins, their value is determined by their original condition as raised and by the conservation process.

[21] Third party coin grading services such as Numismatic Guaranty Company will apply a special label called "shipwreck effect" (rather than a "cleaned" remark) for those that show signs of corrosion or other damage.

"[22] In terms of value, coins recovered from shipwrecks likely hold an appeal as historical artifacts that can be given the marketable status of "treasure".

[24] The largest supply of American mint state gold coins have been recovered from shipwrecks in grades previously unknown to collectors.