Remove cartridge element or D.E. filter from housing. Rinse off any loose material. Thoroughly saturate the filter with water. Spray Filter Blaster over the entire surface area for maximum cleaning power. Allow the concentrated formula to work for 5 minutes. Rinse filter THOROUGHLY with water, then reinstall (foaming may occur if not thoroughly rinsed.) Heavily soiled filter may require a second application. If possible allow cartridge to dry before reinstalling. This allow the fibrous material to "fluff", offering increased filter efficiency.