The freeze spray method is a crock of sh*t.. im not sure who started the rumour that it is a good way to remove Mylar but it is responsible for more ruined playfields than any other method... once again - you are gambling that the mylar has less grip than the paint to primer below it. When removing Mylar gambling is a mugs game.
..Not knocking you Oldskool, but i wish you had posted here first and i would have shouted loudly to steer clear of attempting this... we could have saved quite a lot of paint
Freeze spray method is brilliant for factory MYLAR. I've used it plenty of times for DMD titles. Freeze spray method is absolutely hopeless for CONTACT adhesive - which was a non factory pre mylar solution. I've never seen mylar on an EM. So an EM will always have old contact (unless restorers like Mitch restore and install Mylar), that needs to be removed with the hair dryer method.
This is very handy info to know for anyone else who may want to have a crack at protective removal.