Written by: Gary Dyner

Bills. Dough. Cheddar - whatever you like to call it, currency in the United States has been around since the late 1700s. We work for it. We spend it. Some people save it, while most of us wish to have more of it. But how much do you really know about that green piece of paper in your wallet? Here are some of the most interesting tidbits about American currency:

Money You Could Wear

Like your clothes, U.S. paper bills are made of a combination of linen and cotton. Paper, like notebook paper, is made out of cellulose, which comes from trees. On the other hand, paper money is made from cotton and linen fibers. No wonder your dollar still looks good after a trip through the laundry machine.

All About the Benjamin's

As the highest value bill in circulation, the $100 bill represents 11.9 percent of all U.S. paper currency production. According to the U.S. Bureau of Engraving and Printing, the average $100 bill is expected to last 89 months in circulation, which is four times longer than the $1 bill. Currently, there are about $900 billion worth of $100 bills in circulation. However, most of them are overseas.

Drug Money

Research has shown that 90 percent of paper money circulating in the U.S. contains traces of cocaine. More importantly, $5, $10, $20 and $50 bills are more likely to be positive for cocaine than $1 bills. However, scientists believe the amount of cocaine found on bills is not enough to cause health risks. Realistically, only a faction of these bills have actually been used to snort cocaine. Most of the contact comes incidentally from wallets, cash drawers and money sorting machines.

$2 Bill

Believe it or not, there are currently one billion worth of $2 bills floating around in U.S. currency. However, people see them so rarely that some people think they're counterfeit upon first encountering them. For this reason, many people hold on to $2 bills as souvenirs. Contrary to popular belief, the $2 bill is only worth, well $2. 

The Secret Service

Now this may actually surprise you - the Secret Service, most recognized for protecting the president of the U.S., was originally created to fight counterfeit money. Enacted in 1865, a time when one-third of all bills were thought to be fake. It wasn't until 1902 that the Secret Service assumed full-time responsibility for protect of the president, following the assassination of President William McKinley.

Gary Dyner is the owner of Great American Coin Company. He's also a history buff. When he's not collecting coins, he's studying up on U.S. currency. Connect with him on Google+.