In this study, we investigated the impact of chemical etching on the light output and energy resolution of LYSO scintillators using simple, affordable laboratory equipment. We found that etching with phosphoric acid at temperatures between 180 °C and 190 °C improved the light output and energy resolution compared to mechanically polished crystals, even after minimal etching times. Our results show that with 7.5 min of chemical etching, the light output increase rate is 45.7%, and the relative energy resolution improvement is 12%. •Light output and energy resolution measured for different surface treatments of LYSO scintillators.•A low-cost chemical polishing setup presented, in which multiple scintillators can be polished simultaneously.•Optimum etching time for ideal surface condition determined.