Working with Alliance Model Works PE with plastic film

[Builder 2010]

I tried using AM Works PE 6 years ago and had trouble separating their plastic film that supports the fret from the PE parts without wrecking the parts themselves. I just received two sets of their 40mm Quad Bofors Mounts with Shields and there is that plastic film again, and these are some really small parts. Does anyone have the secret or suggestions on how to separate the PE from their frets AND the plastic film?

[JCRAY]

We used to soak in Laq. Thinner.
Hth! John