Fluxing and skimming repeatedly will get you nowhere near UN-alloying your metal.
I once spend well over an hour trying to do something similar. I was trying to see if I could ever flux to the point where there was nothing to skim. I found out the hard way all I was doing after the first couple of fluxing and skimming, all I was doing was skimming oxidized lead. A futile attempt at purer lead.
My understanding is once alloyed, it is impossible to UN-alloy metals with what we normally have for our home shop.