Found this while burying my cat, how can I clean it?

https://preview.redd.it/n5ah87yix5md1.jpg?width=3000&format=pjpg&auto=webp&s=ad70d42c0c598966bee4ab79170d0088e5633ce0

https://preview.redd.it/vjkw27yix5md1.jpg?width=3000&format=pjpg&auto=webp&s=bf99e197a74e9035af3e9acc28e87e5b90f9c0b5

https://preview.redd.it/rto5x8yix5md1.jpg?width=3000&format=pjpg&auto=webp&s=0262ad75845484a9f41a5d90103cef4af3c7b24f

https://preview.redd.it/gaqmx6yix5md1.jpg?width=3000&format=pjpg&auto=webp&s=c284c2bf33c98c5b99ced2f66ca9c57bdf62629b

It was entirely underground for many years, I will ask in family if they know who it belongs to, but it was all black.

I will take it to a goldsmith in a few days, but I need some project to busy myself.

It fits on my pinky, I would like to wear it as a reminder of her, maybe have initial/name engraved inside