Does this look normal? I am using lead that was originally wheel weight that I casted, fluxed and then poured into ingots. I used a Lee 20# pot to heat the lead. Once the temp reached about 800 degrees I fluxed again using Frankford Arsenal CleanCast Lead Fluxing Compound. The top layer of lead turned a rainbow color. Did I get some tin mixed in my batch of WW or is this normal? I don’t remember the lead doing this when I fluxed it the first time. Any thought?