Seriously mercury is not really hazardous at regular temps. Heating it up or mixing with other chemicals and it can become a bit more worrisome. Plug the bore...pour it in the bore let it sit for a while and voila clean bore..no scrubbing with harsh chemicals and brushes etc. Mercury IS hard to find these days and it is expensive if you do. quite a few years ago a flask(22 lbs??) was about 450 bucks. I was able to get it years ago as I was a gunsmith. I also was able to acquire Sperm oil and still have some of it too...but that is another story
I can't wait to hear about Sperm Oil!
Pretty sure we all know about Sperm Whale Oil though!
Yeah, I know I'm a "dork"!