Lye soap would be period correct, but I use Dawn because it I know is bio-degradable, I can just pour the pans out. The bottle is interesting, my wife got me some by a chance, they have never been used, but they are bottles to grow bacteria in in vacine production.
I also add Chlorox to the rinse water, it will kill any germs that way, just to be safe. The stone jug is for that.