There are three reflectors and one focus lens in a laser engraving machine. Located at the left side of the machine, the first reflector is installed in front of one side of laser tube that emitting laser. The second reflector is set at the left end of the bearing beam. The third reflector is put on the top of the laser head. The focus lens is installed within the lens cone that can be adjusted under the laser head. Laser is first reflected through reflectors and then come out from the laser head. Reflectors tend to gather dust, which deteriorates them and cost laser energy. The first and second reflector can’t be remove out when cleaning them. Dipping with cleaning fluid and using reflector wiping paper to clean reflector spirally from the center to edge. The third reflector need to be took out from the frame and clean it with the same method. Putting it back in the frame after finishing cleaning. Attention: Reflectors need be cleanly carefully. Otherwise, the coating on them may be damaged. After cleaning them, putting them down lightly and avoiding falling off. Being sure to keep the concave face down when installing the focusing lens.