Abstract: Techniques described herein generally relate to cleaning with ultrasonic energy. An example method includes introducing a cleaning solution into a planar cleaning cavity formed between a first inner surface and a second inner surface of a non-rigid container, directing ultrasonic energy into the cleaning cavity from an array of ultrasonic energy emitters disposed on the first inner surface, and removing the cleaning solution from the cleaning cavity by creating a negative pressure in the cleaning cavity relative to atmospheric pressure, so that the first inner surface and the second inner surface are displaced toward each other.