Once you press it you trap water inside making difficult to dry. This can easily lead to mold. I never even fold the screen over on the hash. I just use a dish towel and the screen as a wick to pull water out as I finish the pulling process. By the time I am done pulling and cleaning the nags and stuff the hash is dry enough to run through a kitchen sieve. Using a wooden spoon to push the hash though on to cardboard. This makes the most beautiful powder. Distribute it in a thin layer on the cardboard, 4 days in the ballast room and it is bone dry and ready to puff. Good luck. Peace GS