Review on Premium 4 Pack HAPF60 Replacement Carbon Filters - Enhanced Aftermarket Filter C for Maximum Efficiency by Kyle Gresham

Essentially a pre-filter for my Holmes HEPA filters; The Holmes room filter uses an activated carbon filter in front of each of the two types of HEPA. Initially, the charcoal absorbs a large amount of air odors, but this only lasts for a few days; The real function of this thing is to capture "big particles" before air enters the much more expensive HEPA filters, thereby extending the life of the HEPA filters. When those charcoal filters get dusty (as they quickly do in mine), these things can be cleaned ONCE, and that's with a light vacuum, say a handheld vacuum. Don't try to wash them, it will only splatter carbon and make a mess. There is no point in cleaning them a second time, since by this time they are already clogged with dust. not so the last two deliveries.