a small file of metal or cardboard, for trimming, smoothing, or shaping the fingernails and sometimes having a point for removing dirt from under them.
And by the standards of setting yourself on fire, sawing off your own leg with a nail file isn't so bad.
With a sharp object-a nail file, a pen, or your teeth-make new holes in top hem next to the ones that tore through.
Use fine-grit sandpaper or a nail file to remove any flocking around the leak.
Gently lift the nail away from the reddened skin at the outer corners with the tip of a nail file.
Expelling a student for bringing in a nail file may seem silly, but for some it is a cruel reality.