I had a friend in high school who used to throw away pennies. I found it so incredibly odd to watch her tossing the copper coins into the small trashcan in her room, but it turns out tons of coins — not just pennies — go in the garbage every year. You may think coins aren't worth a damn, but that money that goes in the bin coin by coin really adds up. Bloomberg recently reported on Covanta Holding Corp., an incinerator right outside Philadelphia that uses special magnets and other equipment to sift through the garbage after it's incinerated. Covanta says it pulls out $360,000 a year, which as Bloomberg points out is seven times the average annual income in Philadelphia's metropolitan region. Based on the amount it finds annually, Covanta estimates that Americans throw away a total of $61.8 million every year in coins. What a waste.So what does Covanta do with all the money it finds? The incinerator sells it back to the United States Mint. The Mint then takes the coins and melts them down to be made into new money. Unfortunately, this exchange program was suspended almost a year ago, which means the change is really piling up over at Covanta. It's too bad the employees can't just pocket the change for their next 1,000 vending-machine runs.