GREENING THE WORLD BY CLEANING THE WORLD'S BANKNOTES

Scientists have found a greener, low-cost way to prolong the life of soiled, worn paper bills that would save the world's treasuries billions.

The solution? Literal laundering, or cleaning, of the "dirty" currency.

As banknotes exchange hands, an oily, waxy substance secreted by our skin -- known as human sebum -- accumulates on the bill's surface, disintegrating and discoloring the paper currency until banks have to pull them out of circulation and replace them with new bills. The estimated life span of a U.S. banknote, according to the U.S. Federal Reserve, is between 3.7 and 15 years, depending on the denomination.

But the American Chemical Society reported in the Industrial & Engineering Chemistry Research journal that "supercritical" carbon dioxide, a compound somewhere between a gaseous and fluid state, can cleanse the banknotes free of sebum without disturbing the anti-counterfeit features.

The ACS reports that this cleaning method would offset the nearly $10 billion treasuries around the world spend annually to print new banknotes.

To read the complete article, see: Cleaning 'dirty' bills could save the world's treasuries billions (www.pbs.org/newshour/rundown/2014/01/cleaning-dirty-bills-could-save-the-worlds-treasuries-billions.html)

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