There is a real ultrasonic stylus cleaner, the Humminguru Duo-S. This combines a typical digital scale with the U/S cleaner in a device that looks like a computer mouse. I have one, but I am nervous using it. It requires a pretty exposed cantilever which is to be set down into a small depression filled with cleaning fluid. The cantilever is to rest on the rubber rim of the depression, with the stylus sitting in the solution but not touching the base. If this is done on the turntable platter, you have to be careful not to rotate the platter and rip off the stylus as you press the "mouse" to turn on and off the transducer that does the work. However, it does work, and here is a before and after picture of a new Cadenza Bronze, which was pretty filthy on arrival and was improved by the Duo-S.
Before:
After:
This is not something I would do as a routine, but just when nothing else works. I use a soft stylus brush frequently, a firm Ortofon brush less frquently, a Hudson-type non-U/S vibrating cleaner occasionally, and the Duo-S very rarely.