I am sure you have read these but I thought I would copy and paste for the benifitt of others
Reputable sources declare that the relic was later taken down and fashioned into a silver-mounted drinking cup. Antiquarian and publisher John F. Watson states that the "skull was made into the bottom part of a very large punch bowl, called the infant, which was long used as a drinking vessel at the Raleigh Tavern in Williamsburg. It was enlarged with silver, or silver plated; and I have seen those whose forefathers have spoken of their drinking punch from it, with a silver ladle appurtenant to that bowl." Historian and author John Esten Cooke, in his Virginia, states that the cup was still preserved in the state in 1903. The usage of skulls as drinking cups is an ancient practice. The Roman historian Livy makes reference to northern Italians cleaning and gilding crania for use as drinking goblets; Plutarch and Herodotus record similar rituals practiced by the Teutons, Scythians, and Tibetans.
As recently as 1989, Charles H. Whedbee, a lawyer and state legislator in North Carolina, wrote a volume of reminiscences describing an event of the early 1930s when he visited a law school friend from the University of North Carolina at his home on the coast. Touring Ocracoke, they stopped at Blackbeard's Castle near Silver Lake. It was an odd but convivial evening, spent among rough seamen speaking with the Elizabethan inflection familiar to the area. They drank from what was purported to be Blackbeard's silver-plated skull. Incised around the outer circumference were the words: "Deth to Spotswoode."
heres the link
http://www.shrews.org/public_html/level2/bbaccounts.html