Me and Wicthypoo have been playing around with different mediums, and this is what we have learned:
Muratic acid works on glass, but not Plexi
A variable speed dremel is essential to etch plexi, and lots of practice with different bits/speeds
For sandblasting, a
Paasche eraser for 80 bucks, and an 80 dollar
Home Depot compressor produce very good results:
In the pic below, the "mountian scene" is at 60 PSI, the "Leaf" to the right is at 20 PSI, and the line that looks like snot is our first attempt with a Dremel"