The present invention relates to a novel etching medium for the structuring of transparent, conductive layers, as are used, for example, in the production of liquid-crystal displays (LCDS) using flat-panel screens or of organic light-emitting displays (OLEDs) or in thin-film solar cells. Specifically, it relates to particle-free compositions by means of which fine structures can be etched selectively in oxidic, transparent and conductive layers without damaging or attacking adjacent areas. The novel liquid etching medium can advantageously be applied by means of printing processes to the oxidic, transparent, conductive layers to be structured. Subsequent heat treatment accelerates or initiates the etching process.