Subject: Without using free NaOH, how do you dissolve polyester film?

I am working on a project to chemically dissolve polyester powder paint and 
a clear thin-film polyester decal backer from aluminum parts without 
attacking the aluminum.  I have formulated a liquid chemical that dissolves 
and removes the polyester powder paint when the parts are immersed in the 
190ºF solution for 3 to 5 minutes.  The polyester decal backer, however, is 
not even touched, no  matter how long the time or how high the temp.  Can 
your experts suggest any low or no-V.O.C. solvents, etc, or non etching 
ingredients I might try to dissolve the polyester decal backer?   

Re: Without using free NaOH, how do you dissolve polyester film?