I think you´re definetly doing the right thing! Just get rid of the mylar, it comes off pretty easy with both the freezspray and the hairdryer method. The worst part is to get rid of the glue residue that the mylar leaves behind, that my friend is a bitch. But when the glue is gone and you´ve given the playfield a few buffs with Novus 2, I promise you it will come out great!
Good luck!
And congrats to a great game ( the first one I ever got a highscore on)