Sheets of lead from xray booths are definitely pure, as would roofing and plumbers lead. Any round ingots displaying a number is old style plumbers lead and good stuff. Sometimes you just have to roll the dice and hope for the best. Wheel weights will do OK down to 1/16 but smaller works better with pure. I keep mine separate from each other and do the big stuff from WW with no problems. You can mix it to stretch it some also.