Curated, Not Cleaned

Curation maintains original surfaces while removing debris

Sunken treasure coins recovered from the SS Central America are soaked in a solution to safely lift away ocean deposits. (Photo courtesy Professional Coin Grading Service.)

By Donn Pearlman

Donn Pearlman

There’s considerable misunderstanding by some collectors about cleaning coins. Curation to prudently undo as much “injury” to a coin as possible because of submersion from a shipwreck, a basement flood, or other kinds of environmental damage is beneficial. A few die-hard hobbyists think absolutely no cleaning is acceptable. If that were the standard, many otherwise-outstanding coins would look rather miserable. There’s proper cleaning and improper cleaning, and there is a huge difference between the two. Proper cleaning, often referred to as conservation or curation, can involve the expert removal of surface dirt or unsightly oxidation without harming the original surface of the coin. Improper cleaning can damage the surface and perhaps give it an unnatural color.

Decades ago, while visiting the Rare Coin Company of America (Rarcoa) store in downtown Chicago, an elderly widow brought in her late husband’s coin collection. Unfortunately, she had scrubbed every coin with a kitchen scouring pad because she mistakenly thought collectors only wanted coins that are “bright and shiny.” Store owner Ed Milas told the heartbroken woman that one of the ruined Morgan silver dollars would have been worth about $1,000 but now had less than 1/10 of that value because of the harsh, abrasive cleaning damage.

At a small coin and curio shop at the north end of the Las Vegas Strip in the late 1970s, I saw a dealer clumsily use what appeared to be a dentist’s pick to remove a bit of dust from the obverse lettering of a proof Franklin half dollar. It scratched the coin. 

Nearly all of the fabulous sunken treasure coins recovered from the famous “Ship of Gold,” the SS Central America that sank in 1857, were carefully curated, and the hobby has enjoyed the successful results. A total of 3,134 gold coins were retrieved from the seabed during the last recovery expedition in 2014. With careful, expert conservation, dozens of those coins now are either the finest known of their kind or tied for finest.

Sign Up for the FREE COINage Weekly Update!
Stay in the know. Get the latest news and information from COINage delivered
weekly – right to your inbox!

Scientist Bob Evans, working in the Numismatic Conservation Laboratory at Professional Coin Grading Service, carefully preserved the coins through a complex conservation process that maintained original surfaces while removing debris. The process includes a “bath” in a gentle chemical solution that literally lifts away a century and a half of Atlantic Ocean deposits to reveal the original, pristine surfaces of Mint State coins.

PCGS and Numismatic Guaranty Corporation professionally conserve and restore many coins submitted by collectors and dealers who request these services. The hobby and the marketplace have gratefully accepted this kind proper “cleaning.”

Former Chicago journalist and broadcaster Donn Pearlman was honored with the 2018 Professional Numismatists Guild Lifetime Achievement Award and received the 2015 ANA Farran Zerbe Award.

Want to receive COINage magazine in your mailbox or inbox? Subscribe today!


Please enter your comment!
Please enter your name here