Ok so I made a two part mold of an auto body panel. The top released fine as it was a normal metal body panel. The bottom however did not release. The backside is metal coated with a very hard paint type coating. I used two thick coats of pva, but that's it. I already know I should have used wax, or just a better release agent completely. In any event, now I have a plug stuck in the mold.

I'm going to try soaking it in hot water tonight, and I was going to try heating the back with a heat gun as well. Any other ideas? Worse case would be to cut the mold off of my plug, but that would obviously ruin all of my hard work. The pva didn't do a great job, but I don't believe the tooling gel made a solid bond to my plug either. So I think it will come off with enough work.

Any ideas or advice from any of you more experienced guys?

if you have any access to a small opening to get a rubber tipped blow gun into that usually does the trick. I often just use a blow gun and a wooden wedge. I get the wedge started and then blow air down in between. Worse case so far Ive use a rubber mallet and lightly as to now ruin anything tapped around the part to get it to help release as a buddy pulses the air into it.