A new probe cover must be used for each measurement in order to ensure accurate results. Never use the thermometer without a probe cover as this can cause the lens to become dirty and potentially impact the accuracy of the temperature measurement. The Probe Cover is critical to ensure fingerprints, ear wax or dirt will not contaminate the probe and impede upon the accuracy of the thermometer. If the probe lens becomes dirty it may be gently cleaned with a soft cotton cloth moistened with alcohol. Do NOT use a paper towel. The fibers in the paper towel may scratch the probe lens. Allow forty- five (45) minutes for the probe lens to dry completely before attaching the Probe Cover. Always return the thermometer to its protective case when not in use.