At work (when the ******* thing is working) we have a injector cleaner. It uses a ultrasonic bath and pulsates the injectors via the solenoid. You see the dirty fluid work it's way back out the inlet of the injector.
Yeah, Laty points out this is nothing like ultrasonic cleaning. It’s simply something that anyone can do in the shed that makes them better than they were.
I’d highly recommend his channel. Builds some fairly serious engines in his shed.