How to refill an old powder case?

Hello!

I recently found this old powder case/holder at my great grandmas place, and after cleaning it up, I started to wonder how I could revive this thing. I’m not a big makeup user so I’ve only tried powder once or twice and it was always someone elses, so I’m unsure how to go about this. Should I buy a loose powder and just dump it in? But I’m afraid it will leak out, although the case does have a mesh divider. Also it comes with a powder puff that I assume my grandma used but I would prefer getting a new one, however all I’ve seen are too big or puffy to fit in.

I have attached pictures of the inside and outside! Would also be really cool if someone could help me identify which brand this product comes from in specific.

Thanks!