I looked up Blue Mass because I thought Kentucky John was full of... well mercury. But I found out he was right. However it was commonly used from the 17th century to the 19th century! Come on John that's way back in the sticks!
Mercury is a known carcinogen, easily absorbed through the skin. Not exactly a home project for a recoil reducer. I went to school with a guy who rubbed it on coins to turn them silver. He's no longer with us.
I can see how using one of those pills would eliminate the need for dosing the kids every 6 months with Atgard hog wormer. But that trip back to the pharmacist would take a housewife with steely nerves.
