Hide box important question!

or an exacto-knife may help 'shave' off the sharp edge

A soldering iron can help "melt away" some of the sharp edges, without creating new ones like an exacto blade would...I did it with some of my hides and it worked well.

Yet another idea. I use a sanding sponge on all plasitc that goes in the enclosure. I also use the sanding sponge on all rocks that are sharp and pointy. This rounds them off really nice. Sand them, wash them off good to go.