On July 1, 1990, eight months after the fall of the Berlin Wall, the East German mark ceased to exist.

The 16 million citizens of the soon to be nonexistent country then had until July 6 to convert their East German marks held in cash to West Germany’s deutsche mark on a one to one basis. But it wasn’t that easy. The limit for most people, except those over 60, was 4,000 marks. The rate for amounts above that was cut in half.

A total of 600 million marks, or approximately $333 million worth of the notes, were not redeemed. Most of them are not rare today. Though not worthless, they are readily available from dealers and on Ebay at reasonable prices. 

Inside Coin World 090318 This Week in Coin World: Lesher Referendum dollars and ‘early-date’ cents[1] Features on Lesher Referendum dollars and “early-date” Indian Head cents, and tips on grading Indian Head 5-cent coins, are exclusive to the September monthly issue.

Deutsche Welle, Germany’s international broadcaster, asked another question last month. What happened to the East German marks that were turned in? The answer for coins was easy — they were melted, mostly for their value in aluminum. The paper currency was more problematic. What do you do with 620 million worthless bank notes? 

In 1991, they were all taken and dumped into a pair of sandstone caves near the historic town of Halberstadt in Saxony-Anhalt, close to the former West German border. There, it was thought, the humidity combined with the already miserable condition of most of the notes (except for the printed but never-issued 200- and 500-mark notes), would cause them to decompose. The problem would go away by...

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