Every so often you clean out a closet, open an old trunk, or sort through a relative’s estate and—there it is. A small metal gizmo, a funny-shaped bottle, a tool that looks useful but utterly unfamiliar. You turn it over in your hands and wonder, What on earth did people do with this?

Below are 15 curiosities that recently stumped their finders until someone with a little gray hair—or a knack for sleuthing—supplied the answer. See how many you recognize.