Some of the people opinions on it:

1. Could be an old holder for moth balls–I’ve seen similar devices. Here’s an example.
2. There are two correct answers, it’s an infuser for making iced tea by the pitcher, or its a hanging container for moth balls. It would have a chain about 12 inches long attached to the dimple on top. If you found it in the kitchen, tea. If you found it in a bedroom, mothballs. If it was used for mothballs it will still smell like naptha and will have a white residue inside.
3. For spices in soup. It had a chain on it maybe.
4. It’s an infuser. To make a pot of tea loose tea. Or to infuse herbs into a broth.
5. its for moth balls
6. It looks like it got a lot of use. Maybe it was used to make either a whole pot of coffee or tea. It probably had a chain on top to pull it out of the pot when it was done steeping.
7. I remember these. Tea infuser. The one end had a chain on it.
8. Mothball tin
9. It looks kinda like the thing you put herbs in for stews.
10. I recall seeing these used as dehumidifiers when filled with silica gel. People used to hang them in their closets.
11. I’ve always known them as a picking spice holder. Same as others have said about soup. Once the brine is boiled and spiced, simply pull the ball out with all the spice residue leaving nothing but flavour.
12. I recognise the pattern as something similar was screwed into the lid of a biscuit tin to absorb moisture and keep the biscuits fresh
13. Bouquet garni infuser
14. It’s not used for moth balls they would interact with the metal. It’s used for great pots of tea or mulling spices in wine or herbs and spices in broth so you can take them out. A safety pin through the chain holder and some string will let you remove it but since it’s big you can fish it out. Or you can put lavender or citrus peel in it and add it to a bath.
15. Tea infuser for a small pot.
16. My mom uses that exact device to make tea
17. Catnip container / cat toy.
18. Looks like a massive pod for a Storz & Bickel device
19. Instantly spawned the scent of mothballs in my memories.
20. Why do old people love moth balls?! I’ve never had moths eat anything? What is going on
21. A diffuser of some type. No clue as to what it’d hold, does it have a scent besides metallic?

What do you think? Let us know in the comment!