When should cotton used on the end of a wooden pusher be changed?

Changing the cotton on the end of a wooden pusher after each use is essential for maintaining hygiene and preventing the spread of bacteria and infections. Using fresh cotton ensures that any residue, oils, or contaminants from previous applications do not transfer to the nails of the next client. This practice helps uphold the standards of cleanliness in a nail salon, which is crucial for both client safety and the overall reputation of the business.

While other options might seem relevant, they do not fully address the importance of hygiene in a salon setting. For instance, waiting until the cotton is wet or messy could lead to cross-contamination, and changing it only after each client may not account for situations where multiple applications occur on the same client. Therefore, the guideline to change the cotton after each use is the best practice for safety and cleanliness.