The output energy of quartz-fiber tips for an Er:YAG laser reduces with repeated or inappropriate handling during cavity preparation. The aim of this study was to find the best way to reuse a damaged tip for an Er:YAG laser. An amputated surface of a tip was produced by using the following: group 1 (G1): diamond disk; group 2 (G2): carborundum point; group 3 (G3): waterproof abrasive paper; group 4 (G4): ceramic scissors. An unused new tip was used as a control. The amputated tip surface was observed under a scanning microscope. G3 showed a relatively flat surface compared to G1, 2, and 4, which showed a rough and irregular surface. By analysis using a power meter, although G1 and 2 showed a large reduction of the output energy, G3 and 4 showed slightly lower energy than the control. In addition, the ablated cavity of a bovine dentine plate irradiated for 10 s with each tip was evaluated using a laser microscope. G1, 2, and 4 showed significant reduction of the ablation rate, whereas G3 showed no significant difference. These results suggest that among these four methods, waterproof abrasive paper might recover, to some extent, the tip surface morphology, output energy, and ablation rate.