Over the years I have tried about all the home made fluxes. Now I just drop a pea size chunk of bullet lube in the pot. One thing I would stay away from is commercial clean flux. Back when I was still using a Lee pot, I used it once, Fluxed great, no smoke, But the next time I took the pot out the inside had a heavy layer of rust. And as most know Lee bottom pour pots will mess up with very little junk in them.