I don't know if there are better ways, but I once had to remove
a type of plastic glue from a Duo-Art stack.  I borrowed a heat gun
and heated the glue then scraped off the majority with a straight-edge
knife.  What was left after that I sanded.  It was a hell of a task
but it worked.  I wouldn't recommend to anyone ever using this stuff.

Best regards,
Eliyahu Shahar