Which of the following is not a pneumatic safety rule?

The correct answer highlights an important aspect of safety in working with pneumatic systems. Using any container for compressed air is not permissible due to the risk of accidents, such as explosions or rupture of the container. Safety standards dictate that only containers specifically designed and rated for compressed air should be used, as these containers are engineered to withstand high pressure without compromising safety.

In contrast, the other safety rules mentioned emphasize necessary precautions, such as avoiding exposure to pressurized air and utilizing proper personal protective equipment (PPE). Adhering to these guidelines helps ensure the safety of individuals working with pneumatic systems, thus promoting a safer working environment.