I don't flux at all.

I use a little home made natural gas jet burner and iron pot. I get the lead good and hot and stir it with a small steel rod (a 12" piece about 3/16" diameter steel that I cut from some piece of junk or other with a 4" wood handle attached that I cut from an old broom stick). I suspect I get it hotter than an electric pot would, but really don't know because I've never used one.

Anyway, I stir it then skim the dross with a large aluminum spoon. After two or three stir & skim cycles the lead is as clean as it's ever going to get. Then I reduce the heat and let it cool down a bit before I begin casting.

EDIT/COMMENT ADDED: I seldom have more dross develop during the casting session.