I have over 350 antique vintage gold & silver coins from the USA and around
the world like 1700's colonial coins to US gold pieces of all types. I inherited a
large collection from my father who inherited from his father and grandfather.

I was advised years ago to contact Heritage Auction located in Dallas who is
world renowned for their expertise in all types of world coins. They had an
article about salvaged coins from ship wrecks - the do's & don'ts on cleaning
salvaged coins, mostly about leave them in their original found condition. I
did read about an incident where some doubloons were found off the coast of
Jamaica, and the finder cleaned them only to devalue them by almost 90%

If what you have are salvaged coins, especially gold, consult professional coin
experts before you do anything ....

HERE IS THE HERITAGE LINK:
https://www.ha.com/heritage-auctions-dallas-office.s

Hope the info helps,

Al Varelas / USMC
SS-1654