Our study indicates suspended water films, driven by crossed square-wave electric fields, may act as “washers”, “centrifuges” and “mixers”. Based on our recent model successfully describing experimentally observed electro-hydrodynamical flows in water films, we derive conditions for generating specific rotational flows. Our main findings, which are advantageous for microfluidic devices and basic research, are as follows: (1) the film’s rotational patterns depend on the phase difference $$\Updelta\varphi$$ and frequencies f of the applied fields. (2) For $$\Updelta\varphi=\pi/2$$ and $$f\sim10^{-1}-10^{0}$$ Hz, the film exhibits symmetrical reciprocating rotations, i.e. it constitutes a washer. (3) For $$\Updelta\varphi=0$$ and any f, it exhibits an ordinary anticlockwise (or clockwise) rotation, i.e. it constitutes a centrifuge or motor. (4) For $$\Updelta\varphi$$ with other values and f below 1 Hz, it exhibits asymmetrical reciprocating rotations, it constitutes an asymmetrical mixer.