Which of the following is classified as a single-use item that should be discarded after service?

The classification of cotton pads as a single-use item that should be discarded after service is based on hygiene and safety protocols within esthetics and personal care. Cotton pads are often used for applications such as removing makeup, applying toners, or performing various skin treatments. Once they have been used, they can harbor bacteria and other contaminants, making it essential to dispose of them to prevent cross-contamination between clients.

In contrast, metal tweezers and applicator bottles are reusable items that can be sanitized or sterilized after each use. Facial chairs are durable furniture meant for repeated use and can be cleaned and sanitized between clients. Thus, the nature of cotton pads as disposable items aligns with the best practices in ensuring a safe and hygienic environment within esthetic services.