His filter isn't fine enough.
I go to Michael's art supply and get the finest silk screen filter I can get. You know the kind that used for making t-shirts. Then I cut the bottom of a cardboard box out and I gorilla tape the silkscreen into the bottom of that box. That gives me a nice big area to freeze and shake. I then take whatever fan leaves to whatever buds I don't care about and I chop them up a bit with scissors. Just the really thick parts in the buds. They have to be bone dry if possible for this. Then I take dry ice pellets that I get from the ice cream store and I take a handful and I toss them in with the pot and I shake shake shake over a glass table. At that point the trichomes flutter down and can easily gathered up with a credit card. Just trichomes.