A bathroom exhaust fan loaded with dust moves less air and can sound much louder. Safe household cleaning is limited to the grille, accessible dust, and surfaces the manufacturer allows you to reach with power off; the motor, wiring, and concealed ductwork are a different level of work.
Turn off power before removing the grille
Turn the wall switch off and, if you will reach inside the housing, switch off the circuit as well. Confirm the fan cannot start before removing the grille; do not rely only on the wall switch when your hands will be near wiring.
Vacuum and wash the grille separately
Vacuum surface dust with a brush attachment and wash the grille with soapy water only if the material allows it. Let it dry completely before reinstalling so moisture is not carried into electrical components.
Remove accessible dust without forcing the motor assembly
With power off, gently vacuum dust from accessible housing surfaces and fan blades. Do not bend the wheel, spray cleaner into the housing, or disassemble the motor or electrical connections unless the manual specifically provides for that maintenance.
Noise, vibration, or weak airflow after cleaning may be in the duct
If airflow is still weak, check from safe access points that the exterior outlet is not blocked. Crushed ducting, stuck dampers, or a worn motor require repair; do not turn routine cleaning into unsafe attic or electrical work.
Sources
- American Cleaning Institute — Cleaning Tips — Household cleaning methods, product use and dosing, and material compatibility.