I've have a few Spanish cob fragments from a shipwreck by the name of the Princess Louisa. Many of them have debris stuck to the coin. This one particular coin has lead bb's stuck to the coin. Do you think these bb's are from the shipwreck and became encrusted to the coin? What do you think they are, my best guess is lead shot for a gun.
I also have some other ones covered in a translucent yellow layer. It also looks like epoxy, but that does not seem likely.