We chose acrylic "Plexiglass" for several reasons. While polycarbonate "lexan" is an excellent choice for a lens, acrylic has slight optical clarity advantage. And during our testing and prototyping, we were machining the lenses by hand. We soon learned that acrylic was very easy to repair. Polycarbonate is not repairable. It was simply a matter of end user cost. We will offer replacement lenses at a very reasonable price but there is little reason to ever have to replace our lens. Just polish out the scratches. Our acrylic lenses are also nearly 1/2" thick, negating the strength advantage that lexan has. Sand the affected area with 400 Wet/Dry, then 600 Wet/Dry. Use a buffing wheel on your drill with the Plastic Buffing Compound or White Diamond as Rouge is too fine, to restore the shine. Let the compound do the work - do not press hard or you will "burn" the compound into the plastic.