Like fire dam, Aeroseal has the potential to be sprayed into ventilation systems just prior to the ducting being decommissioned and removed. FireDam  has proven to have varying degree of effectiveness in fixing the contaminants inside.  This product has a specifically engineered appilaction system to ensure adequate coverage and seems like it may be worth a test run.  Working around filters would need to be addressed, but even in a worst case the filters could be changed.