I have looked at this coin! if it is I can make out a skull or a face if you change the angle of light :rolling:
I have to be honest, it looks more like a Halloween pumpkin carving than a skull and crossbones to this Sherlock Holmes. I can see a faint portrait, though, so I'm inclined to agree it's a worn coin. If not, then it looks like a final-stage planchet, because that looks like a rim, there. But, yeah, you need to show us that flip-side. We need all the clues we can get.
The circular pattern to the markings on the 2nd side lead me to believe that somebody ground that coin down on purpose to make it appear to be something it wasn't - like a blank planchet.
Yeah, that circular grinding pattern is bothersome, don't quite know what's up with that. Do know, though, now that that size is stated, that ain't no electrical box punch-out.