Water-based, alkaline cleaning agent specifically developed for the use in ultrasonic and spray-under-immersion cleaning equipment and has excellente rinsing properties. Based on the MPC®-Technology, it reliably removes flux residues from Power Electronics as well as PCBAs, specifically under low-standoff components. Thereby it achieves excellent performance on strongly oxidized and stained copper surfaces and removes oxides and organic contaminations from metals such as heat sinks.