Manual sharpening with a flat-file takes more skill and patience than other methods. However, it's one of the best ways to truly understand and master the art of sharpening. For this method, you'll need a jig to hold the skate in place, a flat sharpening stone, a needle file, and lubricant.

A quick test for a sharp edge is to hold the skate upside down, place one thumbnail on the edge of the blade and gently pull down and away from the blade on three or four parts of the blade. A good, sharp blade will easily scrape a layer of your thumbnail, leaving the remnants on the blade.

Unless you are experienced in grinding skates and have the necessary equipment at home (honed grinding wheel and jeweler's files), you can do enough damage to either prevent you from holding an edge at all or totally ruining the blades that you have to have them replaced.