I have just spent the last 5 minutes trying to get a waxed cotton ball to light with the zippo sparker (from a Zippo blu). It eventually lit but this was in highly controlled conditions and it gave me a sore thumb.

I would give these gizmos a wide body swerve and stick to the $3 Firesteel from DX. It lit another waxed cotton ball first time around. These sparky devices need highly volatile tinder to get going such as the white gas cotton balls or bicycle rubber cement. Even then it has trouble igniting a jet of butane gas about 5-6 mm away. Also the flints internal to these sparkies had a very limit number of strikes, although you can carry around a set of Zippo flints if required.