Although studies of production traces and use-wear in copper and bronze artefacts have been conducted already for a few decades, the influence of the conservation on these items did not receive much scholarly attention. It seems quite surprising, as traceological analyses focus most often on conserved artefacts from museum collections. In the following article, the authors examine the impact the conservation has on traces of production and use-wear in bronze artefacts coming from three Bronze Age hoards: Karmin IV, Paszowice and Lubnowy Wielkie. All deposits have been analysed both before and after the conservation. Our results show that traces of production and use-wear might either become highlighted or fade in the conservation process. Thus, we should be extremely cautious when examining copper and bronze artefacts for the presence of these traces. The problem is especially critical for items which were not examined directly after the discovery but come from the already conserved museum collections.