A German First World War hand grenade was found among a shipment of French potatoes imported for a Hong Kong crisp factory, police said. The grenade was safely destroyed after it was discovered at the Calbee snacks factory on Saturday. “The grenade was in an unstable condition because it has been previously discharged but failed to detonate,” Superintendent Wilfred Wong Ho-hon said. Police detonated it on site. A police video showed bomb disposal officers packing the grenade in a drainage channel at the factory before blowing it up. The grenade was 8 cm wide and weighed about 1 kg.