This question has options. How would someone go about accomplishing this goal?
How do I smooth the edges of the board ?

Pick from: [i] Use a sander with 120 grit paper, you might want to use a drill with a sanding attachment for the holes, or you could also sand it by hand.; [ii] Use a sandblaster at 120 psi, you might want to use a drill with a sanding attachment for the holes, or you could also sand it by hand.;
[i]