I have had good results using a heat gun not a hairdrier because I find the hotter you get the mylar the easier it lifts and leaves the glue fully intact. Removing the glue wont lift letters of the inserts. So get a some cardboard cut a hole the size of a playing card place it over the insert then heat, the mylar should crimple up like old skin it should lift easily. So far I have used alot of heat, that hot you cant touch it and up to now I have'nt damaged one PF as yet.
