Each of the following can be used to clean parts EXCEPT:

The use of tools and substances in cleaning parts is crucial for maintenance and repair tasks in the context of school bus systems and special equipment. Solvents, brushes, and degreasers are all commonly employed to effectively remove grease, dirt, and other contaminants from parts.

Solvents are chemical agents specifically designed to dissolve contaminants, making them effective for cleaning metal and other surface materials. Brushes aid in physically scrubbing the surfaces of parts to dislodge dirt and grime. Degreasers are formulated to break down oil and grease, ensuring that parts are clean and ready for inspection or repair.

In contrast, an air ratchet is a power tool designed for fastening and loosening bolts and nuts rather than cleaning. It typically operates through compressed air to deliver high torque for such applications. While it may assist in the removal of parts for cleaning, it does not serve a cleaning function itself. Thus, the air ratchet is the option that does not belong in a list of cleaning tools.