Which cleaning method should not be used when removing dust or grit from an apparatus?

• A. Vacuuming
• B. Wet wiping
• C. Dry rubbing
• D. Blowing with air

Answer: (C)

The main idea is choosing a cleaning method that removes dust and grit without causing damage or dispersing contamination. Dry rubbing should be avoided because it is abrasive in nature: rubbing dry dust and grit across surfaces can turn those particles into an effective abrasive, scratching finishes, glazing seals, or pushing debris into small crevices. It can also generate static electricity, which can attract more dust and make control of the cleaning environment harder.

Safer options include vacuuming with a proper, clean nozzle and filtration to capture particles without spreading them, and wet wiping on surfaces that can tolerate moisture to lift and trap dust. Blowing with air is sometimes used, but it must be done with caution to prevent blowing grit into sensitive areas or dispersing particles into the surrounding environment.

So, the method to avoid is dry rubbing, because it can scratch surfaces and drive grit into places you don’t want it.