Why is using compressed air to clean a sewing machine not recommended?

• A. Because it can introduce moisture and cause safety hazards
• B. Because it can damage the machine's wiring
• C. Because it leaves residue of oil
• D. Because trapped moisture is dangerous

Answer: (D)

The main idea here is that cleaning a sewing machine with compressed air can introduce moisture into the machine and, more importantly, leave moisture trapped inside. When compressed air is used, especially from home compressors, the air often carries water vapor. As the air expands and cools inside the machine, that moisture can condense on metal parts, in bearings, and around electrical components. Trapped moisture can promote rust and corrosion, lead to electrical problems or shorts, and generally cause wear and reliability issues over time. Because the danger comes from moisture lingering inside, this is the most accurate reason to avoid using compressed air for cleaning.

Other potential issues, like oil residue from the compressor or pushing dust further into gaps, are concerns but secondary to the harm caused by moisture getting trapped inside and causing corrosion or electrical problems.