It’s a phenomenon all travelers can relate to: going through airport security and discovering a few quarters buried in your pockets at the last second. Hurriedly, you toss them into the bin before passing through the metal detector. Once you’re on the other side, you’re rushing to gather your belt, laptop, shoes, and other belongings from the bin, maybe notice those coins at the last minute and think, “Nah. What am I gonna do with 23 cents?” Well, you’re not alone. Hundreds of thousands of travelers leave change behind at the airport, and you know what they say — small change adds up.

According to the Fiscal Year 2018 Report to Congress filed by the TSA, the security agency collected a total of $869,839.56 in 2017, including $36,684.12 in foreign currency that was converted to USD. The report also provides a breakdown of money collected by the airport, with Los Angeles International Airport topping the list with $62,230.79 in unclaimed money.

All of this lost change doesn’t just disappear into the void. Once collected, the money is transferred to hub airports around the country, which send receipts to TSA headquarters. Ultimately, the money ends up in a Special Fund account. The TSA is then allowed to spend that money “for the purpose of providing civil aviation security.” So when you do leave change behind at the airport, you’re a direct (if unwitting) investor in future airport security.