Money, washed and folded

Scientists wash and crumble dollar bills to see how they hold up.
WASHINGTON (AP) -- Andrew Wilson throws his own special load of laundry into the wash: eight white cotton terry towels, 2 1/3 ounces of powdered laundry detergent -- and 25 crisp U.S. greenbacks.
Wash, rinse and spin. When the load is done, it's not the towels he goes for first.
Wilson is a chemist at a Bureau of Engraving and Printing lab that checks how dollar bills survive the torture of everyday life -- whether bucks are spun in a washing machine or dumped in a crumpled mass into an overstuffed handbag.
The bureau, which makes the nation's paper currency, tests thousands of greenbacks weekly.
Picked at random
The dollars are picked at random from larger batches of freshly made notes. But these bills will never make it into cash registers, wallets or handbags. Eventually, they are destroyed.
"What we do here is after the currency is printed, we test the currency to make sure it meets our specifications, which are pretty stringent," said Goutam Gupta, chief of the bureau's Office of Technical Support.
"For example, some people will frequently leave their currency in their pocket and then launder the clothing. So, the note actually has to survive that process," said Gupta, who holds a doctorate in chemistry.
"Is the quality good enough so that [the bill] still retains its clarity and resolution so that it looks like a nice American bank note. We run tests to simulate these actual stresses you'll see in circulation," he said.
The lab tests how well the notes hold up after indignities such as being laundered, soaked in chemicals or folded repeatedly -- technically known as the "crumple" test.
All the tests are important, but it is most troubling if a bill flunks the crumple test, Gupta said. "It is more serious ... because people will take a note and fold it and stick it into their pocket," he said. "That is a much more likely scenario in actual use."
In that test, physicist Virgil Huber cuts a fresh $20 bill into three pieces so it will fit into a special metal contraption. He rolls one slice like a cigarette and inserts it into the device, which squashes it into a pellet. Each crinkly wad is then carefully unfolded and examined.
A bill is tested seven days to 10 days after it rolls off the printing press to provide sufficient time to make sure "the ink is cured," said Valentino DeVito, who also holds a doctorate in chemistry and is manager of technical services. If ink flakes off, the bill can look worn. In general, the bills hold up well because "we have very excellent ink these days," DeVito said.
Rub tests
The lab also conducts a "rub" test, using the same nine solvents. A 2-pound weight with a pad on the bottom is rubbed repeatedly across a bill that has had a solvent poured on it.
Each test has criteria for passing or failing. Most bills pass, officials said.
"In a worst-case scenario ... and something is grossly wrong, the production may have to be destroyed," Gupta said.
Officials, however, cannot think of a time in recent memory when that has happened. Should a note fail, "We have pretty sophisticated scientists ... to specifically determine why there is a failure ... and rectify it," Gupta said.