A method and system for detecting imperfections on a surface of a touchscreen of an electrical device, comprising: swiping a test object, such as a fingertip, a fingernail or a pin, along at least a portion of the touchscreen; producing, by the touchscreen, an electric signal indicative of the test object's contact with the touchscreen; receiving an acoustic signal by an acoustic sensor, during the swipe of the test object along the touchscreen; analyzing, by a processor, at least one of the electric signal and received acoustic signal; and determining existence of imperfections on the touchscreen's surface based on the analysis.