Before: Heavy dust coated the return ductboard passage and flexible duct liner. Process: Hygienic Air connected vacuum-truck collection for negative suction, used micro agitation whips in supply branches, and accessed HVAC components for cleaning. Protective coverings helped shield nearby belongings. After: Photos show exposed return lining and flex-duct ribs with the heavy loose buildup removed, followed by a reinforced closure of the plenum service access. Existing staining and adhered paint or texture overspray remain distinguishable from loose dust.