I have a Swisstool Spirit and a Leatherman Wave. I get both hair popping sharp using the Superior Sharpener that Doug wrote about some time ago. It is convenient to carry about in both an urban setting and in the field. And it works well. My Wave has been neglected and was pretty dull as I have been using the Spirit mostly of late.

After about a dozen or so strokes on the Superior, the Wave's plain edge blade went from really dull to shaving sharp. You just have to sharpen with gradually lightening pressure.