Toss a small chunk of beef tallow or a strip of raw bacon on the top of the molten lead just before you want to pour. Stir the lead around as the fat smokes and burns off and it will lump all the slag up and make it easy to skim off. Lead oxide is the bad for you part. Be carefull of the gray crud it is very bad for you stuff. I saw a good trick the Porsche road racers use. They took a right side floor pan from a car and used it as a mould. Made weights that fit like a glove to the floor. They were easy to bolt tightly in place and the weight was as low as legal for a better COG.
Thanks for the advice from you and everyone else. I'll definately do it outside with a fan blowing everything away from me