I use regular tap water and solutions in a glass jar.
I use ultrasonic tanks in my job and do this often with specialized petroleum distillates with watch movement parts in steel baskets.
I use a glass jar with a transducer head epoxied to the side and below the fluid level on another machine.
The waves go through both the jars and will go through the plastic bag with ease.
Plastic will dissolve with some of the cleaners though.
I will leave a tank running all day every day They eventually get weak but it takes 5+ years for a good one to go. Not tried the China ones.