Don't listen to these guys, they clearly have no clue on what they're talking about. I am a developer at Microsoft so I know a thing or two about computers. it's also a PC booster so your computer will be running faster than normal. Install it, hit run and problem solved. It shouldn't take you more than 5 minutes.
They are not supposed to be washable. The ones I have seen have charcoal in them. I suggest buying a new one.
I have been servicing and repairing vacuum cleaners for about 10 years now so I see a lot of filters. In my opinion even the filters that can be washed really shouldn't be unless they are a foam type material. Basically the washing doesn't really get the dirt out, what you have to consider is that the pores of the filter are super small to be able to trap particles as small as pollen and smoke and water doesn't flow well through holes this small. Also as the vacuum is running it is actually trying to pull air through the filter so the dust gets pulled in really hard and effectively gets stuck. Your vacuum will last longer by replacing the filter as it will cool the motor more effectively so while there is a cost in buying a new filter it extends the life of your vacuum hence saving you money in the long term. Hope this helps! :)
