Bummer. I feel your pain but mine was a batch of epoxy that didn't kick on a wooden boat.

Make a test sample of your covering on balsa and try MEK (if you can find it) or other products. Turpentine has become underutilized as a solvent but still does a great job on some surfaces and it is wood friendly (being a wood byproduct). I get a product called Kleen Strip KS-3 Stripper that will likely remove the ploy. nicely - but I have no idea what it might do to the covering and the glue of the covering. It can be neutralized with mineral spirits when done.