Before placing a hot towel on a client's face, what should a barber do?

Testing the temperature of the towel on the wrist is the best practice before applying it to a client's face because the skin on the wrist is more sensitive and can provide an accurate gauge of how the temperature will feel. This area allows the barber to determine if the towel is too hot, ensuring that they do not cause burns or discomfort to the client.

Applying a hot towel directly to the face without proper testing could be uncomfortable or harmful, making it essential to confirm that the towel is at a safe temperature. While checking the temperature on the back of the hand is a common practice, the wrist is generally considered more sensitive and effective for this purpose. Fanning the towel may cool it down, but it doesn't provide a direct measure of safety. Immediately placing the towel on the client’s face without testing is not safe and could lead to injury. Therefore, testing on the wrist is the recommended and safest approach.