Quoted from trilogybeer:
My friend gets the dry ice from an ice cream shop near his house( I think he pays about $2 a pound ) . I have never used it but he told me that you rub the dry ice on the mylar and it will separate from the glue. Do a small section at a time and never pull hard on the mylar (it should pull off very easy ). Of course you must use caution when handling the dry ice. The glue residue will remain on the playfield and need to be removed. I use 3m general purpose adhesive cleaner to remove the glue.
Ive been using the rapid-tac adhesive remover for the mylar glue.
It works in seconds and cleans off nicely with a little naptha, no issues with clearcoat afterwards. Though I do use rapid-prep before painting for adhesion promotion.
I will never go back to the other methods now, the rapid-tac adhesive remover has spoiled me.