Which action is NOT permitted when using a razor-type callus shaver?

The action that is not permitted when using a razor-type callus shaver is using it on any client. This device is specifically designed for use on clients with thick or rough skin areas, such as calluses, and is intended to be used by licensed professionals who have received proper training in its handling and application.

The rationale for restricting its use involves safety and efficacy. A razor-type callus shaver can pose a risk of injury or non-compliance with health regulations if used improperly or on unsuitable candidates. Licensed professionals are trained to assess the client's skin conditions and determine whether the use of such a tool is appropriate based on individual skin types and conditions. This ensures that they can provide safe and effective treatments while minimizing the risk of cuts, infections, or other complications. The other options are appropriate practices, as they can involve proper use of the tool.