The headquarters of North Yorkshire Police and North Yorkshire Fire and Rescue Servic had been evacuated following a "grenade" scare.
The incident happened in Northallerton at around 1:50pm on Friday 27 October.
The police force have said: "In good faith, a member of the public handed a box of what were believed to be grenades, found during a house clearance, into the police station reception."After evacuating the building, officers put a cordon in place to protect staff, and members of the public.
They also contacted the Army’s Explosive Ordnance Disposal (EOD) Team to deal with the incident.
After the EOD Team arrived, they were able to remove the items, and staff were able to return to the building.
No-one was injured during the incident.
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