that contractors use to

There are three main
types/levels of cleaning
used to clean ductwork
that contractors use to
achieve source removal
of the accumulated dirt
and debris:
The first level is air
washing only. Air
washing is the use of
high-pressure air that
comes from your air
compressor through an
air hose to an air
nozzle. This air nozzle
delivers the streams of
high-pressure air, which
dislodges the
accumulated dirt and
debris. The suction
from the vacuum
collection system and
the high-pressure air
from the air nozzle
move the dirt and
debris that has been
dislodged from the
ductwork into the
vacuum collection
system.