Single-use applicators, such as spatulas, brushes, and cotton swabs, are used during treatments to apply products like masks, creams, and wax. These items should never be reused between clients to prevent cross-contamination. Each applicator should be disposed of immediately after use, ensuring that no bacteria, oils, or other contaminants are transferred from one client to another. This practice is crucial for maintaining a high level of hygiene and preventing the spread of infections or skin irritations.