Older ducts need care, not just suction
Duct systems from the 1960s and 1970s were often built with fiberglass lining or interior insulation that cannot survive aggressive brushing. A high pressure approach can damage the liner and put fibers into the air, which is worse than the dust you started with. We inspect first, use methods suited to the material, and tell you honestly when a section is deteriorated enough that cleaning is not the answer and replacement is.
