Was smelting wheel weights I had gotten at my local shop. Poured in a batch of clip on weights. Usually I just sort out the stick on from the clip on and stir often, and remove anything that doesn't melt. I don't let my temp get high. Anyway I was working on it and got an important call that I thought would take 5 minutes but it took 20. Till I got back to my smelting, the clips and weights that had not melted were coated with a thick oatmeal like substance. Uh-oh. Thought it might be lead that had not melted right so I tried stirring vigorously. It only made it worse. So I scooped it out along with the clips, and tried to skim the top. Then the top turned gold, Then a dark purple. That did it, I dumped the whole mess into my scrap bucket. Fortunately it was only 25-30 lbs, but still irritated me. But I still think I did the right thing in dumping it. My guess is that it got too hot and melted some zinc into the mix.