A HEPA filter is an air filter, designed to remove dirt, dust, hair and impurities from the air, while trapping those items in the filter. The filters should be cleaned at least once every thirty days to remove this buildup and replaced with a new filter every 6 months. If the filter is not routinely cleaned and replaced, the filter will lose efficiency.
Remove the HEPA filter from the air purifier. This process will vary based on the brand and type of filter you own. If you are unsure how to do this, read the User Manual for the filter model you own.
Dampen a soft cloth in water. Squeeze the cloth to remove excess water.
Wipe down the HEPA filter surfaces. Continue rinsing the cloth and wiping the surface until it is clean.
Allow the filter to air dry before placing it back in the filter.