I watched several YouTubes on sharpening knives, YouTube - knife sharpening. I'm definitely no expert but... I taught myself and most of my kitchen knives are considerably sharper than they used to be and I think with more practice I'll improve. I used some sort of a stone to sharpen my knives. The stone is aprx. 3" x 8". That being said, I've got an apple corer/slicer I use weekly that's pretty dull. This isn't a cheapmadeinChinaboughtatChinaMart use 50x then toss and be a good consumer and buy a new apple corer/slicer. It's older... possibly 50 years at least and has good weight to it and I'd like to sharpen it. I have a photo of it that I could add if....I knew how. It looks similar to this, http://www.towsure.com/home/images/products/a256.jpg. I bought a hand sharpener of some sort that is about the length of a pencil only instead of being round, it's triangular in configuration. Although small enough to get between the "spokes", I don't believe it's coarse enough. Any guidance appreciated.