Shane
I just had a mylar job yesterday and cut 10 mill mylar to the required shape and cutouts. I did it all in vector mode with my 80 watt Trotec. Cuts were clean and fast. There was a minimal amount of smoke residue on the back which I cleaned with isopropyl alcohol.

Settings for my 80 watt were 40 power, 2.0 speed and 500 hertz. The 7.5" x 3.5 pieces took just a few seconds each.