Next time you go through the metal detector at the airport, don’t forget to collect your lose change from the conveyer belt.

Last year, travelers left $674,841.06 in change rushing through airport security, according to Transportation Security Administration calculations. In 2013, plane passengers left $638,142.64.

“TSA makes every effort to reunite passengers with items left at the checkpoint, however there are instances where loose change or other items are left behind and unclaimed. Unclaimed money, typically consisting of loose coins passengers remove from their pockets, is documented and turned into the TSA financial office," TSA spokesman Ross Feinstein told Fox News.

And if you're wondering if one airport collects more money than another, the answer is a resounding yes.  In 2014, New York's John F. Kennedy Airport collected the most of all the U.S. airports at $42,550, while Seattle-Tacoma International Airport, for example, collected just $11,977.47.

Due to federal law passed in 2005, the agency gets to keep any monies found in those little plastic bins for "security operations," according to Feinstein.

While a six figure bonus may be welcome by TSA, airports around the country have come with alternative ways to use that spare change.

At Denver International Airport, airport agents placed collection containers by airport security checkpoints in 2013. In the past two years, the airport has collected over $170,000 to help support citywide homeless programs.

Phoenix Sky Harbor set out collection boxes just before the Super Bowl last year and collected over $1,000 in February alone to suppose USO operations at the airport, according to airport spokeswoman Heather Lissner.

Unless you feel like leaving that friendly TSA agent a nice tip, suggest a collection box at your local airport—but don’t forget to check those conveyer belt bins in the meantime.