Postal Savings System history:

• On April 27, 1966, the system stopped accepting deposits. • The Postal Savings System officially ended July 1, 1967. About $60 million in unclaimed deposits was turned over to the Treasury Department to be held in trust. • Under a law of Aug. 13, 1971, the Treasury was authorized to turn the money over to the various states and jurisdictions involved. • The Postal Savings System Statute of Limitations Act, Public Law 98-359 of July 13, 1984, provided that "no claims for any Postal Savings System deposit may be brought more than one year from the date of the enactment of the act," concluding this chapter in postal history.

So, no Postal Savings System certificates have been redeemed since 1985. The Web site for the National Postal Museum has pictures of the certificates and further describes the program.

Your certificate stopped earning interest in 1966 to 1967. Prior to that, it earned 2 percent annual interest. A dollar invested at 2 percent for 32 years would be worth $1.88. If it had earned interest through to today it would be worth approximately $4.16. 

Selling it as a collectible will depend on its condition, but it's bound to be worth more than its cash value, which is zero. A recent eBay auction closed with a winning bid of about $40 for what the seller described as a mint condition certificate.

To ask a question of Dr. Don, go to the "Ask the Experts" page, and select one of these topics: "financing a home," "saving & investing" or "money."