What safety precaution should be taken with steam machines?

Maintaining a safe distance from the client's skin while using steam machines is essential to prevent burns and other skin damage. Steam machines emit hot vapor, which can lead to overheating and scorching if applied too closely. By keeping an appropriate distance, typically around 12 inches, the aesthetician ensures that the steam provides its benefits, such as opening pores and improving circulation, while minimizing any risks to the client's skin.

The other options suggest practices that do not align with safety standards. For instance, using steam on all skin types without caution ignores individual variations in skin sensitivity and condition. Turning up the heat for better results could exacerbate the risk of burns and isn't generally advised. Applying steam directly to the skin neglects the important principle of thermal safety and could cause immediate harm. Thus, ensuring a safe distance is a fundamental precaution that promotes the client's safety and comfort during the treatment.