A few companies do make ultrasonic cleaners that are designed for flammable solvents, but they aren't common.

The easiest option is to just fill a plastic food bag with solvent, throw your part in, seal it with a clip and float it in your ultrasonic bath. The bag contains the vapour for safety, and it's easy to switch between different solvents and solutions.

That is next generation sous vide. Just controlling temperature is ho-hum. Getting it to just the right ultrasonic vibration to "cross-modulate the adipose frequency" is next level.

And someone is already doing it:

https://besservacuum.com/en/ultrasonic-food-treatment-machin...

That's a quite elegant solution I hadn't considered before.