Numismatic Rarities Certainty Act of 2006

Numismatic Rarities Certainty Act of 2006 - Amends federal law governing coins and currency to provide that any coin, medal, or numismatic item made or issued by the United States before January 1, 1933, that is not in the possession of the federal government as of the date of the enactment of this Act, shall not be considered to be property of the United States unless it is reacquired by the United States for value given in a sale or exchange.

Requires transfer to the Secretary of the Treasury of any coins, medals, and numismatic items that were struck or made by the U.S. government after 1932, which were never issued by the U.S. government, and yet come into its possession.

Prescribes guidelines for disposition of such items, including historic preservation, public display, and sales at public auction.

Requires the Secretary to compile an inventory of all coins, medals, or numismatic items that are either: (1) in the possession of the U.S. government; or (2) on loan to, or were at any time presented to or retained by, any person or entity (other than in accordance with a specific requirement of federal law), regardless of when such item was struck or made.