Which item should be used to clean the inside of a gauge glass?

The use of a cloth wrapped around a wooden dowel for cleaning the inside of a gauge glass is appropriate for several reasons. This method allows for effective cleaning without scratching the glass surface, which could occur if a harsher material like steel wool were used. The wooden dowel provides a rigid yet gentle tool that can be easily maneuvered inside the glass tube, allowing the user to reach different areas for thorough cleaning.

Using a cloth ensures that any dirt, scale, or residue is wiped away, maintaining the clarity of the gauge glass. This is essential for ensuring accurate readings of the water level inside the boiler, which is vital for safe and efficient operation. The combination of the dowel and cloth allows for control and reduces the risk of inadvertently damaging the gauge or leaving lint behind, a concern with materials like paper towels or rags that might break apart or leave residue.

Overall, this option strikes a balance between effectiveness and safety when cleaning sensitive equipment like gauge glass.