This is third of a six-part series that takes you behind of the scenes to watch preparations for marketing material retrieved in 2014 from the historic shipwreck:

In mid-February Coin World senior editor Paul Gilkes spent a few hours at the headquarters of the Professional Coin Grading Service, speaking with Robert Evans, the chief scientist and historian on two separate sets of explorations of the wrecksite of the SS Central America.

Above, Evans makes it clear that each coin does not get the same amount of treatment. Though the solution is the same strength, some coins require more time for it to work, so some patience is required. Evans briefly relates a little about the chemistry of the solution being used to soak the coins free of the geologic deposits they acquired from their long stay on the seafloor, prior to their long-awaited display.

SS Central America reveals thousands of new findings The treasure recovered from the wreckage of the SS Central America from 1988 to 1991 has been widely studied and dispersed in the marketplace.

Ship of Gold, part 2, ready for another numismatic voyage SS Central America treasure salvaged in 2014 to go on public display.

What is the SS Central America and why is it so important to numismatics? Steamship was carrying precious cargo when it capsized off the South Carolina coast in 1857.