A beachcomber brought home what she thought was a rusty old plate. Months later, she learned it was a land mine

(CNN) – Back in April, Jayne Wilson found what she thought was an old plate lying on the beach. The truth is a bit more explosive.

Wilson, who works as a private home health aide, was walking her client's dog around sunrise on Indian River Shores beach, in Florida. The avid beachcomber likes collecting sea glass, so she examined the sea shell beds as she walked -- just in case something caught her eye.

And something did -- lying atop the sand that day was what looked like a plate, maybe lost long ago off a Spanish ship.

So, she took it home. For months she chipped away at the shells and barnacles crusted onto its surface, storing it in a lunch box cooler filled with water.

Then, on Tuesday, there was a post on a community web page about a man who found a land mine. A friend sent it over to Wilson, saying "Jayne, is that the thing you have in a cooler on your living room floor?"

That's when Wilson realized what she had stored at home. For the past nine months, she'd been chipping away at a land mine.

She called the Indian River Shores police, who told her to evacuate her home while they notified a nearby Air Force base to pick up the mine.

Wilson, though, reasoned that if it hadn't gone off in the last few months, it probably wasn't going to go off now. Instead, she brought it to her client's house and decided to leave it outside for the authorities to collect.

Indian River Shores Police Capt. Mark Shaw told TCPalm that similar finds occur "all the time" in the area.

“You got to be extremely careful -- you never know,” he said. “We treat it as live and able to explode at any second.”