Yep, to flux you just need something to burn on top of the lead to pull the junk to the top. I used candle wax the last time that I did it and it worked great. Another thing that I do now that I am getting better at the casting game is to stir my pot every 50 balls or so, just in case anything has settled to the bottom. (My pot is a bottom pour). Casting balls or bullets has worked fine for a couple hudred years or so, so I think that it should work fine for me. The methods and tools that we are using are a far cry from the way that our ancestors where doing it over the campfire with an all in one tool and probably the same pots or pans that they ate in. I enjoy casting, its fun and relaxing to me.