I only recommend small spots of mylar be applied to playfields for specific
areas of high wear. Such areas that usually receive heavy wear are magnetic
areas (such as magnasave), eject hole landing spots, circles around pop
bumpers, or anywhere the ball will drop from a ramp onto the playfield.
Mylar tends to lift from the playfield, especially over playfield inserts
(those flush mounted lighted plastic lenses), slow the ball motion, and
appear dingy and dull after extended use. For these reasons mylar is
usually not the best solution to protect an entire playfield, but it is fine
for spot use.