The Code38 is fitted with a curved plain-edged foil blade designed to have its edge sharpened using a knife sharpening steel. A standard chef's knife steel is ideal.
Rest the knife steel on the blade of the wine key so the steel is just resting on the blades edge.
With moderate to light pressure simultaneously pull away and along the blade.
Once at the end of the sharpening stroke, repeat again 2-3 times
Repeat this procedure for the other side of blades edge.