How often, and how, do you clean your stylus?

I clean only when it sounds like it needs it. Couple of times a year with many hours of playing in between. With this hobby, I don't look, or listen, for problems that aren't there. 

That's a very personal and inappropriate question. For shame!

As it is not mentioned, I will add it to the items that can be used to remove particulate from a Styli.

The product is Jewellers Putty, used to pick practical of Gem Stones.

Making a Match Type tool using a Tooth Pick will allow for it to be used as a probe, or a small ball to lower the Styli onto are both OK methods.

If a TA has a Cue Lift Lever, and the Volume is not turned down, the Styli can be lowered to just above the Groove, prior to it making full contact, this will show immediately if a particulate is present that will effect the sound to be produced.

If all is quiet above the Groove 99% of the replays will be quiet when making first contact with the Groove.

The isn't too many options to use as a safeguard to particulate collecting at the styli throughout the replay.   

Anyone use that Hummingbird Ultrasonic stylus cleaner?

I've heard that you don't want to use cleaning fluids on the stylus like alcohol. But maybe the Hummingbird uses water?

Onzow zerodust works amazingly well for me and as far as I can tell it doesn’t leave residue behind which is the main culprit. It will always be a problem unless you live in a cleanroom or heaven forbid use your table with a dust cover on. Not so sure about magic sponge. They are cellular and use melamine as the a cleaning abrasive. Unless you’re dropping the stylus straight down and back up I would use extreme caution. It might be viable solution but with the zerodust you can see easily what is being removed.