Ninety-seven untouched Super Mario Bros./Duck Hunt cartridges were found in a Waukesha storage unit, a haul collector Jason Ganos called a once-in-a-lifetime discovery.
The cartridges were reportedly part of a box of 100 Nintendo sent to Wisconsin for destruction in the early 1990s, but they were forgotten for about 30 years instead of being scrapped.
Their value is unclear because the game itself is common, but collectors say the uncirculated condition and a newly identified motherboard back-label variant make the batch unusually significant.
Five copies could become the first Nintendo or NES cartridges ever to receive a PSA 10 grade, and three are scheduled to go to Golden Auctions on Aug. 12.