You can sharpen the outside bevel of the hole punch by hand on a stone, belt sander, sand paper or whatever you may have.
Then you can use a 240 grit tapered cartridge sanding roll to clean up the inside of the hole punch. Just stick the cartridge roll in the end of the punch & give it a couple twists back & forth by hand & your punch will be sharp.
Also they come in different diameters. These are a 1" diameter at the large end & ⅜diameter on the small end.
Hope this may help.