.....version patissier!! 
1) Freeze spray a bit at a time (compressed air will work also, I
guess) and pull up mylar gently.
2) Repeat 1) until all the mylar is removed (be careful not to let it
fall pack on the playfield again during removal, otherwise it'll just
stick again)
3) Get some isopropyl alcohol and wet the sticky area.
4) Before the alcohol evaporates, sprinkle some flour (used for
cooking) on the wet patch
5) Gently work the flour into the glue/alcohol with the finger
6) Hey Presto - glue disappears (well actually the glue dissolves into
the alcohol and is absorbed by the flour which goes lumpy and just
sits on the surface of the playfield).
You wont believe how simple, safe, clean and quick this method is.
en video:
http://www.youtube.com/watch?v=v5TtArrymBA&feature=player_embedded

1) Freeze spray a bit at a time (compressed air will work also, I
guess) and pull up mylar gently.
2) Repeat 1) until all the mylar is removed (be careful not to let it
fall pack on the playfield again during removal, otherwise it'll just
stick again)
3) Get some isopropyl alcohol and wet the sticky area.
4) Before the alcohol evaporates, sprinkle some flour (used for
cooking) on the wet patch
5) Gently work the flour into the glue/alcohol with the finger
6) Hey Presto - glue disappears (well actually the glue dissolves into
the alcohol and is absorbed by the flour which goes lumpy and just
sits on the surface of the playfield).
You wont believe how simple, safe, clean and quick this method is.
en video:
http://www.youtube.com/watch?v=v5TtArrymBA&feature=player_embedded