When a Minnesota bank becomes the nation’s fourth since December to fail (as happened Friday), and a Minnesota credit union gets hit with a cease-and-desist order from the state for being in the red (as happened in mid-May), it may be time to sew a wad of bills into a mattress, hide a bankroll under a floorboard, and bury a cashbox in the backyard.

Or better yet, do what The Associated Press reports that a Briggsville, Wis., man recently did: find a box of money that’s been stashed away since the Great Depression.

Dan Deming was tearing down an old shed on his Milwaukee-area farm when he noticed a metal box in the rubble containing $1,700 in bills dated from 1928 to 1934. The currency’s condition was too poor to interest collectors in his windfall, so Deming redeemed the cash with the U.S. Treasury Department for face value.

As our sister site, the Washington Independent, reported last week (a day before the failure of First Integrity Bank in Staples, Minn.), Wall Street is ready for 150 to 300 banks to fold in the next two years as the mortgage foreclosure crisis continues. With peace of mind from reforms that were put in place after the Great Depression of the 1930s and the savings and loan debacle of the 1980s and 1990s, many observers are relatively sanguine this time, in part because after years of mergers, there are simply fewer banks around to fail.

In theory, if the mystery lock-box depositor who unintentionally paid it forward had instead managed to find a reliable Depression-era bank or stock market investment in which to put what Deming guesses was his or her life savings, the money in the box might today have a value of $54,000 to $228,000. But finding such a bank would have been a crap shoot, considering that the annual number of Depression-era bank failures peaked at more than 4,000 in 1934, the year the latest bill in the box was printed.