Dear Kid,

Think you know about money? Think again.

Pennies used to be made of copper, but now they are mostly zinc and nickel. A penny (generally accepted to be worth one cent [or less]) now costs 2.4 cents to make. Somehow, this simultaneously makes no sense (it costs more to manufacture than it’s worth) and all the sense in the world (government).

On the other hand, only 8% of the global currency is cash. But you knew that most money is digital. You are part of the digital age. Maybe you are the digital age. In any event, think about how often we pay with a credit card (a lot) or transfer “money” between accounts (a lot). Digital cash.

The ink on paper money (which is actually cloth, not paper) is not just regular ink. It has trackable, magnetic, and—wait for it—birefringent properties. Birefringent means color changing. Like my hair.

Ben Franklin is the only non-president to appear on bill.

Money (the physical kind) doesn’t last forever. These days, a farm in Delaware mulches worn out bills into compost. Coins that are taken out of circulation are run through a waffling machine (which basically makes them the opposite of recognizable coins) and then they are recycled.

But Americans throw away about $62 million worth of coins every year. Hey, ‘Murica! Feel free to send it to me rather than losing your change in your couch or throwing it out with the burger wrappers!

Bacteria live on most money. Most of it won’t make you sick, but the flu virus can live on money for up to two weeks. The older the bill, the more likely it will have nasties on it, like salmonella or E. coli. Wash your hands.

Love, Mom