How to cut HIPS?

I have just started my first vacuum forming project and I was wondering what you guys used to cut out the plastic after it's formed. I am using 1.5 and 2.00 HIPS and making an inner and outer shell so I need to cut holes in the outer shell.

 

Dremel with fiberglass cutting wheel.
After it's cut close to what you want then switch to the sanding drum, then down to files and sand paper.

 

Thanks, that worked a treat.