Chicago's O’Hare International Airport and Midway Airports have installed boxes for travelers to dispose of recreational marijuana before getting on a plane, since traveling with marijuana is illegal.

The cannabis amnesty boxes are stationed just past each Transportation Security Administration checkpoint, says a news report. 

The boxes are owned by the Chicago Department of Aviation and serviced by the Chicago police. Police officers will regularly empty the boxes, file a report for the items inside and dispose of any surrendered marijuana as they would narcotics, the report says.

The boxes were installed at each airport last week, just as legal weed sales began in Illinois.

Las Vegas' McCarran International Airport also has specially designated bins to dispose leftover, legally-purchased marijuana before traveling. The green receptacles are bolted to the ground in “high-traffic” areas outside the airport and its car rental area.