An Ontario police department is warning residents not to bring unexploded military munitions to the station after a woman walked in carrying a live World War II grenade, according to the NY Post. The incident happened at an Ottawa-area Ontario Provincial Police detachment, where officers said a resident arrived with the decades-old explosive after finding it while cleaning out her basement. The Post writes that the 77-year-old woman was immediately told to leave the grenade outside the building as a precaution. “You don’t know what condition they’re in, whether they can still explode,” Ontario Provincial Police spokesperson Michael Fathi told the Ottawa Citizen. The department stressed that anyone who discovers old grenades, bombs, shells or other military explosives should never transport them.