This Midway YouTube vid tells a quick method how (btw that's Midway Gun Parts, not silly midway at the fairgrounds):
https://www.youtube.com/watch?v=x-HdLKcSu1w
I'm using this method on an Cooey 84 I'm overhauling.
He has another one on padding shotgun wood that keep on cracking, which is here:
https://www.youtube.com/watch?v=AAMspI1BeyI
I need some release agent to go ahead with this one. Industrial Paint & Plastics will be where I will look.