I've been using an ultrasonic cleaner for my air brush since the mid 70's. I use lacquer thinner for enamels in a small pyrex flask I bought at the hobby store in the chemical set selection. Just put water in the cleaner and sit the flask in the water, the cavitation transfers into the flask with no problem.
For aqueous based paints I just use water with a bit of dish washing soap,gets all the gunk out in a snap. For tiny parts I use a mesh screen in the shape of a bowl so I don't have to go grabbing around for them in the muck at the bottom.