Coin Cleaning Process
 April 9, 2006 -- Ron Pierson
Coin Cleaning Photos: Step One
All artifacts are tagged and assigned individual identification numbers at the time of recovery onboard the salvage vessel. The exact DGPS co-ordinates, as well as bottom terrain, and depth are recorded by the captain then entered into the Corporate Database.
Pre-conservation photos are taken of each coin, measurements are also taken at this time and all information is recorded in the Corporate Database.
John Corcoran, conservator/diver, records the weight of each coin and notes any anomalies.
The first step of the actual conservation process is to remove some of the hard concretion encasing the coin.
A 10% mixture of muriatic acid and water is used to soften and deteriorate the encrustation. The bubbles mean its working.
There is no need to subject the delicate silver to excessive amounts of acid, so after approximately 10 minutes in the solution the still partially encrusted coin is rinsed in fresh water.
Only a small section of the metal must be accessible to attach the alligator clip.
The coin is attached to a stainless steel alligator clip and stainless steel wire.
The coins are placed into the electrolysis tanks, beginning the electrolytic cleaning process.
The electrolysis tank consists of Soda Ash and water, with a stainless steel plate (anode) and a low voltage current. During the process of electrolysis hydrogen bubbles are released and the chlorides are expelled from the metal.
Coin Cleaning Photos: Step Two
Electrolysis time differs for each artifact. The average amount of time required for a silver coin is 3 to 4 days.
At least once during the process the coins are removed from the tank, rinsed in fresh water and the build up of concretions, which remained on the coin when placed in electrolysis, is removed with a soft brush.
Coin Cleaning Process Continued:

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