After you get your lead very hot and you have it all cleaned, take the mold and dip the corner of the mold (not the entire mold mind you) into the lead in the pot. If the lead is hot it will not stick to the mold. Hold the mold in the lead for 30 seconds. That will heat the mold. It is important that once you start casting you stay casting and do not let the mold cool or you will get wrinkles and actually spots on the ball. If as you are casting and the balls start getting hard to come out of the mold, it might have cooled down. Just re-dip it and start all over.

Be sure and smoke the mold good before you start casting and you should be fine. I just use a old Lee melter pot over a gas fire and it has worked for me.