You know the cute, clever little replacement air filters for those
room air purifiers? The filters that, after two or three
replacements, cost as much as the air purifier did? Forget 'em. Just
buy your normal three-pack of HEPA furnace filters from the hardware
store, cut them down to size, and stuff 'em in the purifiers. Be
careful not to cut yourself on the metal ribs, and make sure you get
the air flow direction right. I got this tip from an Amazon review of
an overpriced mini-filter. I tried it out, and sure enough the air
gets cleaned just as well for much cheaper.
The dignified don't even enter in the game.
-- The Jam