I think packing tape, Saran Wrap, duct tape, etc. are great if you don't need a perfectly smooth part.  Some of my molds, the "good" side is the "mold" side.  I want them to be as smooth as possible.  Some things get covered with 1/4" foam and then leather, so small imperfections will disappear.  But I have some magazine pockets that need to be smooth.  I don't want to spend hours doing body work on the part after it comes out of the mold.

 

Thanks again for all the good ideas.

 

Mike