Lay it flat with two edges downon a sharpening stone. Push and flip, push and flip, push and flip. You just sharpened all six edges of the three blades. Do one push for each side and flip until it is sharp.


BTW, you can use a diamond stone, Arkansas stone, fine file, ultra find sand paper, etc... etc... PersonallyI would use either a diamond stone or Arkansas stone, no need to get elaborate since these have been sharpening blades for years and years.