I had read about using stearic acid for fluxing bullet metal. Well, I tried it this weekend, and I was amazed. I was schmelting a magical alloy of range lead, WW, sheet lead, linotype, and a little solder. BTW, I ended up with 150# of BHN 10 (measured after 12 hours) ingots
I fluxed with paraffin and got my usual pretty good results. Just for grins, I added a couple of teaspoons of stearic acid and lit it off. After it all burned off, the melt surface had an incredible shiny quality that I have never witnessed (except in dreams) While paraffin, wood chips, and pine resin had always left a powdery waste on top, the stearic acid left a blackish goo that was pretty easy to skim.
It reminded me of results you get when you add rosin core solder to the melt.
I think it's worth a try.