I simply keep the heat turned down so it is not overheating the bottom, Plus I start stirring as soon as I get enough liquid to do so. I have never melted a zinc yet, they all float to the top with the clips. That is not to say I do not check them, I do. But we all are going to miss one or two. And I do not put the whole load in at once. I will add 20 lbs. or so each time after I scoop out the trash and flux. I will end up with a hundred lbs. in the pot eventually but not all at once.