Is it acceptable to wipe off dirt from the lens surface of Photoelectric Sensors with alcohol?
No, it is not. The lens of the Photoelectric Sensors are basically plastic. Do not use organic solvents, such as thinners or alcohol, to wipe the surface. The lens surface may become clouded or cracked. Gently wipe away dirt with a dry cloth or use water.
The same applies to the Sensor case if the case is plastic.