I was kind of distraught when my bagless hepa-filtering vacuum seemed to not "suck" as well after I'd been using if for a while. As much as I tried to "tap" out those darn filters like they suggest, I never seemed to get them clean enough. Plus, I'm lazy and cheap and didn't want to go buy new filters for the thing.

So last spring I took that sucker outside with one of those compressed air cans you use to clean computers. I dusted out all the nooks and crannies, blasted the filters until they looked almost new - and now it works great again! A few caveats: 1) definitely do this outside, on a non-windy day - or you'll drown yourself and your neighbors with dust, if you're sensitive, wear a dust mask and goggles/glasses, you'd be amazed how much crap those filters can hold! 2) I honestly don't know if blasting the filters with compressed air will reduce the efficacy of the allergen-filtering aspect of the hepa filter system, but my allergies aren't that bad: I mostly like how it traps the dust and doesn't shot it back into the room, and they seem to do that just fine.