Eight homes were evacuated after a live mortar bomb was found in Buxton.
A man found the “very rusty” device while out walking on Saturday afternoon – and took it back to his home in Brierlow Road, Harpur Hill, before alerting police.
Officers called the army bomb disposal team from Catterick Garrison at about 3.30pm, evacuated the homes and set up a cordon.
A Derbyshire police spokesman said: “The army bomb disposal team made it safe and took it away.”
People were allowed to return to their homes at about 9.30pm.