To be accurate, infrared thermometers need to be be kept free of dirt, dust, moisture, fog, smoke and debris. When these conditions are present, you may want to consider using another tool for measuring surface temperatures such as a surface temperature probe and non infrared thermometer.
Always take the time to clean your infrared thermometer after exposure to dirty, dusty, smokey or humid conditions. You should also plan a regular cleaning every six months or so. Particular care should be taken to keep the infrared lens or opening clean and free of debris.
To clean your infrared thermometer:
Never submerge any part of your infrared thermometer.
Store your thermometer between 4-65°C and protect it from extreme temperatures while in storage.
Always ensure you protect your infrared thermometer from drops or knocks.