Using Sandpaper
Step 1
Sand the cut edges of the plexiglass with 100-grit sandpaper. The 100-grit sandpaper will remove the most uneven areas on the edges of the plexiglass. Make sure that you are not generating much heat as you sand the plexiglass. Heat can deform the plexiglass.
Step 2
Graduate to the 200-grit sandpaper and sand until the plexiglass is nearly smooth to the touch.
Step 3
Finish by using 400-grit sandpaper in the sanding block if you are using one. The plexiglass should feel completely smooth and have a polished appearance.
Using a Hand-held Rotary Tool
Step 1
Insert a sanding grinder bit equivalent to 100-grit sandpaper into the rotary tool and tighten the bit. Grind off the roughest edges.
Step 2
Switch the grinder bit to a medium grit and continue to smooth out the rough edges. Keep wiping off the dust generated as the tool polishes the surface.
Step 3
Install the finest grinder bit into the rotary tool, tighten it down, and keep refining the edge until it is completely smooth.