Many mornings, Julie Lisi and her husband, Michael Lisi, head to a thrift store in Jupiter, Fla., to look for treasures. They will walk around for 30 minutes or so, and usually leave empty-handed.

“We are retired, and it is something to do,” Ms. Lisi said.

But on a trip to the store last Wednesday, they were floored. There, sitting on a shelf, was a baseball glove that belonged to their son Christopher Lisi, 40 years ago in Willoughby, Ohio, where the couple raised their family and still spend part of the year.

“My eyes just happened to glance to it,” Ms. Lisi, 78, said in a phone interview. “It didn’t really register. Things were whirling in my mind.”