When I tried to make a two piece POP mold the first time, I used PAM on the raw POP, and the new POP stuck to it badly.
I posted my bad results, and got lots of good advice.
Thanks to the members here, now when I make my POP molds, after I make the first half, I dry it in the over at 170 degrees for an hour, with the door ajar.
Then I coat the mold face with D2T epoxy, mixed really well and then cut 1/1 with denatured alcohol. I brush the mixture onto the POP and it soaks right in. I brush on at least three coats, one right after the other, and then let it set up.
Once the epoxy sets, I spray the face with PAM, and put it face down over the second half of the mold that's filled with fresh POP. I immediately clamp the two halves together, and turn them over so the half with the fresh POP is on top.
I tap the top of the mold with a rubber handled screw driver to try and get the air bubbles in the POP to migrate up and away from the mold masters.
Once the new POP had set, I open the mold, clean off any flash or crud, and do the oven and D2T treatment on the new half.
I still spray PAM on both mold halves before I pour my plastic. It really helps to keep the plastic from sticking.