A thrift shop in St. Stephen got more than it bargained for when it accepted an old box of donated military memorabilia.

Volunteers at Frugal Furnishings were sorting through the items late last week when they found an un-detonated World War II hand grenade.

"I was in the back and Sue says, 'Look at this, that's a grenade, or something," recalled Mary Atkinson.

"So I just looked at it and picked it up and set it down and I said, 'Well, give Donna a call," she said, referring to Donna Linton, co-ordinator of the Volunteer Centre of Charlotte County.

Mary Atkinson, volunteer at Frugal Furnishings

Mary Atkinson, a volunteer at Frugal Furnishings, handled the undetonated grenade, not realizing it was real. (CBC)

What they had found was an American Mk. II fragmentation grenade.

It had actually been in the store, sitting in storage, for more than two years, said Linton.

"At first they were shocked and surprised," she said.

"They thought maybe it was a ceramic ornament. I was told by the volunteers they did handle it quite a bit," she said.

Eventually they called the RCMP.

"In all my [years of] service, and that’s just over 30 years now, I don't ever recall something like this," said Sgt. Bob MacKnight, of the St. George detachment.

"Once we confirmed their belief, which, our belief was the same as theirs [that it was in fact a real grenade], we cleared the building, secured it and contacted our explosives disposal unit," he said.

The bomb squad destroyed the grenade.

Although it appeared the explosive material had already been removed, the pin had not been pulled, so the WWII relic was still considered a threat, officials explained.

The lethal radius of a grenade is usually two to three metres, plus the splinter effect, experts have said.