Army bomb experts were called out after a hand grenade and a Second World War Spitfire mortar shell were found at a household tip.
The Bemersley Household Waste Recycling Centre near Biddulph, Staffordshire, was cordoned off following the discovery.
Staffordshire Police said four suspicious items were left in one of the scrap metal units. The Spitfire shell was destroyed in a controlled explosion in a nearby field.