That eMag thing looks like a re-branded version of what I bought in Tokyo last May but have not used because it scares me a bit in that I fear it might loosen the bond between stylus and cantilever. Or the Onzow.
Here's why I wrote that waiting until the stylus "sounds like" it needs cleaning (which will be a different threshold for each of us) is whistling in the dark. Because if you wait that long, it is possible that your stylus has been permanently damaged (assymetrically worn) by junk accumulated on it that you did not sense was there. I realized this when I started using a lab grade microscope to examine styli on various cartridges, none of which "sounded like" they needed cleaning. Many of them were gunked up, not so much on the stylus tip as at the base of the stylus and along the cantilever, which cannot be good for maximizing the capacity of the cartridge to trace the groove accurately. So I recommend periodic inspection using a decent magnifier of some sort, which I would do every few months, depending upon use, but not after every LP by any means. If you do that, you can monitor the effectiveness of any cleaning method you routinely use, and alter the method if you see problems.
