I was shooting for 20/1, had a pretty clean mix, but added some plumbers lead and a corresponding amount of tin. Boolits are sometimes dirty looking, kind of frosted in one spot(consistent location on the boolit). Fluxed this stuff 10 times at least to try to cure the problem, to no avail.The cooled pot afterwards has these huge voids and weird spots in it. is this some kind of odd metal in the mix that causes this, or does it look normal?