Hold a black light next to the lamp in a dark room. New oil lamps are held together with glue, and new glue fluoresces in black light. Old lamps have glass parts that are fused, so they don't glow ...

cover the entire side of the lens that we have made with black tape. Press the back of the flashlight to turn it on and check that it emits ultraviolet light perfectly. It is now ready to use.