Abstract: The cleaning of a surface is monitored in real time using a number of physical measurements. In particular an electrochemically inactive material is removed from an electrode while the electrode is able to detect a redox system in the bulk liquid. The removal of the material from the surface is monitored as an increased Faradaic current at the electrode surface. This signal is used to assess the ability of the cleaning method employed, in this case the application of power ultrasound to the system, as a function of the position of the electrode with respect to the sound source. It is shown that, depending on the conditions employed, surface cleaning is driven by different mechanisms. In order to validate these findings highspeed imaging of the system was undertaken and the results correlated with the electrochemical data. In addition a number of novel electrodes were also employed to assess the cleaning efficiency as a function of the electrode geometry employed. Implications for surface cleaning in the presence of power ultrasound are suggested.