I zoomed in as close as I could get on this greenish CD 143 Canadian Pacific beehive and since the threads on the pin were so deteriorted I was able to just push the insulator off with my extension pole.

It's a MLOD with fine embossing, no periods and a very narrow wire groove so I'm guessing it's from the mid to late 1880s and I'm amazed something this old was still in service.

I'll be honest it has a couple of tiny hairline cracks in it but it's still a decent looking insulator.