We’ve got our mind on our money and chemistry on our mind.

That’s right folks, this week on Reactions, we’re talking cash.

Believe it or not, there are stacks of chemistry-rich facts about money,

so we compiled a list of our four favorite facts about the almighty dollar.

Fact 1. The Federal Bureau of Engraving and Printing

use washing machines for quality control. The Bureau produced about 26 million

bank notes a day last year, which totals around $1.3 billion dollars.

With all those bills being printed, you want to make darn sure that they’ll

hold up in rough conditions, so the Bureau

has some really high standards to keep. The printers have to consider a huge amount

of variables when testing money for durability. So at the end of production, bureau scientists

put their dollars through a beating with washing machines, cement mixers, crumple tests,

and a host of other challenges. Fact 2.

Now it may sound like a weird test, but the washing

machine really isn’t all that out of place. After all, paper money is made up

of the same stuff as your clothes. Well, cotton and linen to be more exact.

Both of these materials are derived from cellulose, which is the most abundant organic polymer

and the basic structural element of woody plants.

Cellulose is very strong and resistant to breakage in water, which makes it

an excellent material for cash. For added security, little tiny red and blue

fibers are added to the paper mix to make counterfeiting

much more difficult. Embedded metal or plastic threads

are also woven into bills. Go ahead and pull out a twenty and take a

look to the left of Jackson’s head – here you’ll

see an embedded thread that reads “USA twenty”.

Fact 3. If you have a dollar in your pocket,

chances are you’re also carrying cocaine. That’s right people, but don’t worry

this doesn’t mean you’re a criminal. In 2009, a team of chemists lead by researcher

Yuegang Zuo at Umass Dartmouth discovered that

roughly 90% of paper money in the US has cocaine residue on it, and 95% of the bills

in Washington, DC carrying cocaine. Now this doesn't mean that the world’s gone

Scarface and that cocaine use has gone way up.

When a cocaine-contaminated bill goes through a money counter or an ATM, tiny amounts of

cocaine spread to nearly all of the bills in the machine.

Zuo’s team used a super fancy instrument called

a gas chromatograph-mass spectrometer to accurately measure the cocaine content of paper money

from five different countries. Of these five countries, the US carried

the highest average amounts of cocaine.

Fact 4. To ward off counterfeiters, money is printed with

infrared ink amongst other specialized inks. The inks used to print cash are composed of

inorganic pigments, varnishes, Alkyds, and drier agents like calcium carbonate – the

same chemical used to make red fireworks!

Go ahead and whip out that twenty again and take

a look at that shiny looking “20” on the bottom

right of the front of the bill. A special, optically variable ink is used

to produce the color changing effect that allows

the text to change from green to bronze. Infrared inks are used to hide secret features

in bills, which makes counterfeiting really difficult.

Infrared inks are undetectable by the naked eye, but do absorb light

at higher wavelengths than we can see. These kinds of inks are extremely hard to come by

and to print with them requires serious precision.

So they’re no use in trying to go and print your own money, you’re going to fail, ok.

For more information about the chemistry involved in printing money at the

Federal Bureau of Engraving and Printing, make sure to check out these ACS Webinar videos.

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