The official Dyson video and the pictures in the owner manual are USELESS when it comes to cleaning this filter.
I followed the instructions religiously for the first six months until my Dyson became unusable. When I tried to use it, it smelled horrible and it would IMMEDIATELY go into the pulsing on and off business. High power was unusable.
In use, dirty air is sucked into the BIG end and goes down the INSIDE of the fabric cone. It is pulled THROUGH the fabric and exhausts through the motor. Any dirt in the air settles DOWN into the SMALL end. If you follow the official Dyson instructions to wash this thing, all you do is push wet dirt down into the small end. As it dries, it begins to mold or something and that is where the HORRIBLE smell comes from.
TO WASH
There are three little plastic tabs that hold the fabric part of the filter onto its plastic frame. They are right under the big end, next to the openings. You might have to use a flat tip screwdriver the first time to force the tabs out of their holes. When you get the three tabs out of their holes, you can then pull the fabric part off of the frame.
1 Remove the cloth part from the frame.
2 Turn the LITTLE END UP.
3 Wash under running water.
4 Using warm water and dish soap, gently massage the filter from little end to big end. You will be amazed at how much dirt comes out the big end.
When I removed mine the first time, I found a glob of filthy, smelly gunk down in the small end. I cleaned it out, then washed and dried the fabric part. My Dyson cleaned like it was new again! Imagine that . . . A PROPER cleaning was all it needed . . . .