I purchased about 200 lbs of sheet lead (it was removed from a doctors office). Would like to melt down and pour into my Lyman mold. I did purchase the Lyman Big Dipper pot. Just not sure on what and how to do. There is some sort of glue (thin layer) on one side of the sheet lead, do I try to scrap it off? Do I need to add other alloys? Any help will be appreciated and start my journey to casting boolits.