Unfortunately, repeated experiences show that most Police bomb-squads don't know whether a munition is from the 19th-Century, or first half of the 20th-Century, or second half. Also, they tend to not know whether the munition is active, or inert, or a dummy for army training practice.
Two examples:
Here in the Richmond area a few years ago, a local police Bomb Squad declared that a Geode (a rock) found in a car at the Richmond Airport was "iive" -- and took it to the police range, where they blew it with a shaped-charge. Strangely, they couldn't find even a single tiny piece of it afterward. (If it was made of metal, there would have been some pieces in the disposal hole.)
Also here in Richmond, back around 2000, the Bomb Squad (or Army EOD squad, I don't recall which) declared that a 10" iron/steel ball found during construction near the Tredegar Iron Works site was too dangerous to even be moved elsewhere for disposal. So they strapped charges to it and blew it on-site. The blast made the 10" ball hop into the air, but that's all. It turned out to be a 10" Solid ball.
Because the Jacksonville Florida grenade was found during leaf-raking, it must have been dropped in the yard in very recent years. You can buy Army practice-training "dummy" grenades easily at miltary-surplus shops and online. But we'll probably never know for sure what it was, because the TV-News crew was apparently unable to obtain any photos of it for the news-report video.
Note: Post has been modified ONLY to correct several typo-errors. For example, I do know how to spell the word disposal -- but sometimes I can't type it right.
