Guards discovered the problem after an inmate cleaned up a tray of food that had been thrown against a wall.
The Beatrice Daily Sun Reports Sheriff Millard "Gus" Gustafson said last week that after the inmate threw the food, a guard went looking for cleanup supplies.
When she returned, she noticed the mess had been cleaned up -- and not by her or any other jail workers.
A guard later noticed that the cell door keyhole could be turned -- without the key -- just enough to pop the cell door.
Turns out inmates could slide their hands far enough out of the cell door to reach the keyhole.
Jail workers later found another door lock that was so worn that it could be popped open, too.