Before: Photos document attached dust on flex-duct lining and deposits on the return and plenum surfaces, including pale deposits recorded as suspect growth during inspection. Process: We accessed the air handler and openings for vacuum collection under negative suction and used micro agitation whips at supply openings. After: Comparison photos show exposed flex-duct ribs after source removal. The plenum photos document sealed surfaces and connections after coating and seam work. Existing staining and material conditions remain separate from the loose buildup removed.