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.
Step one
Rest the knife steel on the blade of the wine key so the steel is just resting on the blades edge.
Step two
With moderate to light pressure simultaneously pull away and along the blade.
Step three
Once at the end of the sharpening stroke, repeat again 2-3 times
Step four
Repeat this procedure for the other side of blades edge.