I bought one put my old copper none valuable coins through it and it turned them to slick discs in no time. It came with a bag of tiny ball bearings. I definitely wouldn’t put anything of any value anywhere near one!
The only use I get out of mine like dondo’s said is once in a blue moon cleaning up modern coins still in currency, £1,£2 and 50p coins but even with them you have to be careful how long you leave them in for. Prob’s take me 20 years using it for that purpose to pay for itself.
In my experience it was a waste of money.
This is just my opinion & hope it helps

You only go round the block once! So you might as well go round it with a smile on your face
Manticore
Nox 800
Garrett EuroACE
Garrett At “pro” pinpointer (I’m personally along way off that description though)
![BigGrin [88/]](./images/smilies/88_EmoticonsHDcom.png)
carrot