Shark Navigator Vacuum Foam and Felt Filter Kit Set NV22L Pro XF22 4 Filters. Directions for Washing the Foam and Felt Filters: Remove the Foam and the Felt Filters from the Filter Holder. Rinse with warm water until the water runs clear. Squeeze filters and let air dry overnight before replacing. Insert the included replacement filters while others are drying. DO NOT operate the vacuum without ALL the filters in place or operate the vacuum with WET filters.