Q: I’ve been a fan for many years. I found this “thing” in my mother’s house when she passed away. I would love to know what it is and what it’s used for. As you can see, it is in two pieces and fits together. On the handle it says, “Made in England.” That is the only marking. There is a fish cutout on the bottom and it is slightly curved. Any ideas?

A: Your mystery tool is a sardine can opener. The slot at the bottom would slide onto the edge of the lid, so you could roll it back. Then slide in the shovel-shaped piece on the end of the key and you have a handy tool for lifting out the sardines. Opening sardine cans has always been a challenge. The sardine can with a key was invented in 1889. Cans came with keys soldered to the bottom. Some modern cans have the key and can wrapped in a paper label. Now most sardine cans open with a pull tab, invented in 1959. Very few cans open with keys today. Your key is worth about $25 for its novelty appeal.