A worker at a Florida Goodwill store found a hand grenade in a bin of donated items, prompting an evacuation.

Police determined the grenade was inert, and it's the second time a year that a Goodwill in the area has gotten a donated grenade.

Visit INSIDER's homepage for more stories.

Thrift stores are a great place to find clothing bargains, funky tchotchkes and souvenirs from family trips that nobody wanted. But every so often, you can find something really unique.

Just ask the folks at the Goodwill thrift store at 1082 SW Gatlin Blvd. in Port St. Lucie, Florida.

Shortly before 5 p.m. on May 15, Port St. Lucie Police and St. Lucie County Bomb Squad responded to reports of a "military hand grenade" found inside of a donated bin, according to Sgt. Lisa Carrasquillo, a PSLPD spokeswoman, who in an email described what happened next.

Police learned a Goodwill employee discovered the hand grenade inside of the bin that had been donated to the store. The employee notified her manager and the manager called 911. Police arrived on scene and evacuated everyone inside of the store. Police also evacuated the parking lot surrounding the Goodwill Store for safety reasons for about 90 minutes.

About 40 people were evacuated from the area, Carrasquillo said. No other businesses were threatened; therefore, no other evacuations were necessary.

A St. Lucie County Bomb Squad technician arrived on scene to assist with the investigation. The technician determined the hand grenade was inert, took custody of it and the evacuation order was lifted.

The grenade appeared to be a Mk.II fragmentation hand grenade, often referred to as a "pineapple" because of the segmented protrusions from the explosive device's core, designed to send fragments of metal screaming at those unfortunate enough to be on the receiving end.

Deployed from 1918 through the 1960s the "Deuce" is considered by some to be one of the most sought-after pieces of ordnance by American militaria collectors, according to inert-ord.net, a collector's website.

This was the second time in a year that an inert grenade was found in a local Goodwill store, according to TCPalm.com, which first reported this. It is unknown, said Carrasquillo, who donated the bin that contained the latest hand grenade.