Anyone Here Know How To Safely Clean A Boyd's Battery Without Damaging It?

Hello,

I was able to acquire a Boyd's Battery recently and it is pretty dirty/grody and I was wondering if anyone here knows how to go about safely cleaning it without damaging it.

The reason that I want to clean it is to see if it actually works. Not in the sense of what they were originally advertised to do in a quackery sense but in the sense that does it actually produce an electrical charge from nothing more than human sweat.

Boyd's Battery was invented as a quackery cure all in the 1870's when electricity was all the rage in regards to medicine. It supposedly works on galvanic corrosion principals and can produce an electrical charge with no moving parts with nothing more than coming into contact with human sweat. It was a pendent that when worn would cause the skin around it to tingle as the electrolytes in sweat came into contact with it producing a mild electrical charge. I am curious if this is actually the case in reality.

Picture of the item in question below, any thoughts or advice would be helpful. Thanks.