Carbon fiber and epoxy can be used to create a new look for your prop masks.  You can create a whole new surface and give your mask a whole new look.

From Youtube Matthieu Libeert

In this extended video tutorial I’ll explain you how you can skin any part you found around you with carbonfiber – carbon fiber (fibre).
By skinning parts you will add carbonfiber on top of your original part. By doing so you will add weight, but you will also add stiffness to your part. You can compare skinning parts with carbonfiber with flattening parts before paint with bondo. You add layer after layer and sand inbetween to get a high gloss finish at the end. In this tutorial all materials used are from easy composites.