I must confess I'm more than a little disappointed we haven't seen or heard much in the way of substantive follow-up, lately, on this question from Mr. Fremer, WAM Engineering, Wally Tools, Onzow, DS Audio or whomever. Seems all the audiophile gods have been silent for a while, now.
I contacted Mobile Fidelity a few days ago to see what they might recommend with regard to stylus cleaning and, also, to see if they had any thoughts about the Onzow Zerodust or gel cleaners, in general. They've never failed to respond, yet. When (or if) I get a response, I'll share. In the meantime, here is my experience with regard to using the Onzow:
I haven't been using the Onzow for very long. Only records I've ultrasonically cleaned, first (even new ones), have been played on my relatively new TT & cartridge. I use the Onzow before and after every side. All my records are in anti-static poly sleeves and have been very well cared for and stored since I bought them. All the records I've played have been treated with LAST record preservative. I use an AudioQuest carbon fiber anti-static brush before & after every play. For what it's worth, I also use a Michell record clamp. One change I'm going to make, now, is to use the AQ brush BEFORE I use the Onzow and immediately after, right before play, instead of using the Onzow, first, and brush, second, right before play. Probably obsessive overkill but what the heck! Doesn't really take that much time.
When I use the Onzow, I do not free-hand it (i.e. raise it to the stylus by hand). I set in on a little block, on the plinth, at the proper height, so I can use the TT's cueing lever to lower the stylus onto and off of the Onzow's gel pad. I do this 2 or 3 times, moving the block & Onzow around just a little each time to give the stylus a clean landing spot each time. When I first started using the Onzow, I didn't notice any deposits on the gel pad at all and wondered if my records and stylus were really that clean. However, lately, I've noticed ever so tiny little black spots or specks, here & there, on the Onzow gel pad. I'm assuming this means the Onzow is doing what it's supposed to do. Is it getting everything? I've used the magnifying cover of the Onzow box and, also, a very small hand-held stylus microscope I have to examine the stylus. However, both of these are extremely limited and don't really give as good a view of the stylus as I'd like. I just might invest in a jeweler's loop or something better. From what little I have been able to see, the stylus looks relatively clean. I can't really say with any degree of certainty what the black spots on the Onzow gel pad really are. My assumption has always been that it's probably whatever dust & crap the Onzow picks up from whatever the stylus picks up in the grooves. My non-scientist's assumption has always been that these tiny black specks are probably PVC shavings from the records, dust and whatever other crap hides in those grooves. LAST treatment or not, considering you've got a highly polished diamond doing a complicated dance in those tiny little PVC grooves, the friction and heat going on in there has to be wearing away some amount of PVC. Anyway, that's what my non-scientist's mind without an electron microscope has always thought.
As for continuing to use my Onzow or going to a liquid cleaner, dry stylus brush, stylus brush with distilled water, ultrasonic stylus cleaner, combination thereof, etc, etc, etc,, I haven't decided, yet. There are SO MANY opinions on this! It would be nice to see a showdown review or several showdown reviews on this with a healthy amount of scientific acumen applied, including, of course, electron microscope shots. However, I doubt this will ever happen. Something like that would put some people & products out of business. Then again, there are some minds impervious to science who would just go on using whatever they firmly believe in, anyway. So, I don't see the harm. Might even be a good marketing investment.
I've used a stylus brush and liquid cleaner in the past and would really, really hate to go back to that! Music Direct has said, in the past, that they use the Onzow and, occasionally, Mofi LP#9 for stylus cleaning. Don't know if they are still using that approach. I'm not sure if Mofi LP#9 is a non-solvent cleaner, per se. Fremer says he subscribes to the use of non-solvent cleaners and uses Audio Intelligent stylus cleaner, an enzymatic formula. Aren't enzymes just another solvent? If memory serves correctly, I believe LAST stylus cleaner is also a non-solvent formulation. I'm sure there are probably other non-solvent type liquid stylus cleaners and all sorts of other concoctions out there, as well. As for the Onzow gel breaking down over time, I can't remember where I read this; might have been reviews, but I do recall reading that this gel is supposed to last a very, very long time; virtually forever, even after cleaning (by running warmed distilled water over it). Nothing lasts forever! And then, of course, there's Magic Eraser, BlueTack, etc., etc.
What's a poor confused vinyl head audiophile to do?
In the end, I suspect we may very well learn that many, if not all, of the different reputable stylus cleaning approaches are effective; just different. Either that, or we will all be left to our own devices and this will prove to do be much ado about nothing, like many things in audiophilia nervosa.