PETERBOROUGH, Ont. - A southern Ontario family who kept First World War artillery shells in their home for decades acted responsibly when they chose to relinquish the heirlooms to police, military explosive experts said Friday.

The Peterborough family, who turned the shells over for testing on Thursday, ran great risks by keeping the ordinance in their home and even using them as doorstops, they said.

Capt. Canton at Canadian Forces Base Trenton, who declined to provide his first name, said no civilians should ever risk handling military ordinances regardless of how safe they may seem.

"It's military hardware, leave the stuff alone," he said in a telephone interview. "If you identify something as a military ordinance, do not touch it, put a flag there or something like that, call the police. You never, ever assume you can handle the stuff."

Master Cpl. Fraser, a military explosive expert who also declined to provide his first name, said the Peterborough family held onto the First World War shells for years before being advised to turn them over to the police. The shells had been in the family's possession for at least three generations and had sometimes been used as doorstops, he said.

The family, who declined requests for an interview, contacted Peterborough police on Thursday to assess whether the shells posed a threat, Fraser said. Military personnel were eventually called in to test the shells, which had been fired and had no casings.

Experts will conduct tests on the shells to determine whether they still contain explosives, he said.

Fraser said it's common for people to hold on to ordinances as souvenirs, saying both active and dormant shells are often discovered in former military training zones as people renovate homes or excavate land.

"When they train, most explosives go off, but a lot of them do not, and that's where the safety and the hazards come in," he said. "The ones that don't go off, they're a ticking time bomb."

Canton praised the Peterborough family for acting responsibly when they became aware of the risks associated with their heirlooms.

"It doesn't matter how long. At some point the guy recognized what he's got is not good and decided to do the right thing."