Interior-cleaning equipment carries whatever the last cabin released. Vacuum filters load with dust, hoses trap debris, extractor tanks retain organic residue, nozzles clog, brushes hold particles, towels store oils and chemistry, and drying fans can redistribute contamination. Performance can decline before a tool appears broken.
Maintenance restores a known hygiene and operating baseline. Emptying, cleaning, drying, inspecting, labeling, segregating, laundering, replacing, and recording components preserves airflow, spray, recovery, contact softness, chemical identity, and odor control. Without that baseline, the next vehicle receives hidden residue and misleading test results. Clean storage then protects that restored condition until reuse.