Old tin that has been used/temperd and the lead solder isnt scrubbed clean is ok. The solder will oxidize and form a coating that keeps the lead from leaching out. Old water lines from the 1920-30-40s were lead (remember Mr Plum in the study with the lead pipe)its water pipe. If you have amalgam fillings in your teeth you have had murcury in your mouth and thru your system. As far as the draw off you want it as close to the bottom as possible. you can still draw off as you go and tip it at the end of the day. Under boil things are mixing so much that you will be ok as far as daily draw off goes.