Before: Comparison photos document dust and debris inside the return passage and deposits on supply and bath-fan components. Process: We accessed the air handler and openings for cleaning and connected vacuum collection under negative suction. Protective covers shielded furnishings during source removal. After: Photos show exposed duct and return surfaces, plus cleaned bath-fan housings. Existing corrosion, staining, and material discoloration remain separate from the buildup removed during service.