The outgrowth formation in inorganic thin films is a dramatic problem that has limited the technological impact of many techniques and materials. Outgrowths are often themselves part of the films, but are detrimental for vertical junctions since they cause short-circuits or work as defects, compromising the reproducibility and in some cases the operation of the corresponding devices. The problem of outgrowth is particularly relevant in ablation-based methods and in some complex oxides, but is present in a large variety of systems and techniques. Here we propose an efficient local electrochemical method to selectively decompose the outgrowths of conductive oxide thin films by electrochemical decomposition, without altering the properties of the background film. The process is carried out using the same set-up as for local oxidation nanolithography, except for the sign of the voltage bias and it works at the nanoscale both as serial method using a scanning probe and as parallel method using conductive stamps. We demonstrated our process using La 0.7 Sr 0.3 MnO3 perovskite as a representative material but in principle it can be extended to many other conductive systems.