Discolored Boolits

Background: New to me Pro Melt (First Use), 3rd casting session with a new NOE 460-315 GC WFN using COWW w/ approximately 1.5% pewter casting at 800, 775, 750 and 700.

This was the third session with this mold, cleaned and degreased. Previous session were short (10-25 pours to season the mold but no discoloration of the boolits. Last night, I decided to cast some out of coww so I got out the new to me clean promelt, loaded about 10 lbs of coww in it and plugged it in. The ingots melted and no impurities noted, added the tin and stirred. Very minor slag. Casted about 20-25 cycles and finally got the hang of the pro melt but I had discolored boolits kinda like sitting in dirty water. Mold was hot so I wasn't going to degrease again with solvent but had no wrinkles, good fillout, sharp edges ect, just discolored projos from one half of one cavity.

I think I just anseared my own question. Headed out to degrease the mold and try again. First time working with coww.

Well, I degreased/cleaned the mold and casted another 100-150 projos and still have an occassional discolored bullet, kinda dark swirls on half of a bullet.

Need photos. Guessing that the discoloration is coming from dirty alloy. Maybe rust from emptying the pot between uses? Too much sprue plate lube? Can you describe your fluxing techniques?

Is imagine discoloration is either contaminate related, wether it be sprue plate lube or grease or whatever on the mold. Or a cold mold. I've had cavities show a different finish when one half of a cavity was cold.

I think your still cooking some of the cutting oil out of the mold.
try wiping the swirls off with a rag.

Thanks for the ideas. Tried with a preheated mold and down to 675-700 and still an occassional half stained projo. Good fill out ect just alittle odd even after degreasing. I'll try and wipe a few before sizing tomorrow. And post a few pics.

Fluxing with a couple of peas of bees wax, stir, cook and skim. The alloy is some of the cleanest I've worked with so far, minimal debris collected from skimming.

No worry if boolits are good. I doubt it is oil in the mold. Maybe the degreaser has something in it.
When I make a mold I have used everything from WD-40, cutting oil and water soluble oil. Hot water and Dawn cleans it out and first boolits are perfect.
I used acetone and other cleaners but soap works best.