What should be avoided entirely when servicing oxygen systems?

The correct answer highlights the importance of keeping oxygen systems free from moisture. Oxygen systems in aircraft are designed to operate under high pressure and can be highly reactive, especially when combined with other substances or contaminants. When moisture is present, it can lead to corrosion or ice formation within the system, which can obstruct the flow of oxygen and potentially create hazardous conditions. Ensuring that the systems remain dry is crucial for maintaining their integrity and functionality.

In contrast, using non-oil-based lubricants is a standard practice in oxygen systems, as oil can be a fire hazard when exposed to oxygen at high pressures. Clean rags are typically used in maintenance to ensure that any surfaces are free from debris, and oxygen is often used for purging systems to remove contaminants; these practices are acceptable when performed correctly. This emphasizes the focus on moisture control as a critical safety consideration in the servicing of oxygen systems.