Use a garden hose with good water pressure. The
filter should have an arrow indicating airflow
direction. First spray off the filter from the
opposite side of the arrow. Then from the other
side.You can repeat this process several times if
needed. If the filter is very dirty, spray it with
a detergent first and let soak for a few minutes.
Then thoroughly spray off with water.
Just be careful not to use too much water pressure
or damage could be done to the filter media. When
the water runs clear and the filter is clean,
simply shake off excess water and return to
Water pressure from a sink or bathtub is usually
not sufficient for cleaning. A vacuum cleaner with
attachment can also be used to clean the filter if
there is no access to a garden hose.