There are a ton of different types of kitchen knife sharpeners out there, but there’s a basic rule you can apply to all of them to keep them clean: don’t use chemicals. Whatever you do, don’t use chemicals. Most knife sharpeners are made out of steel, and if you’re really feeling ritzy, you can get diamond-edged steel to retain your blades for absolute ages, but the fact of the matter is chemicals can kill your sharpening edge.\r