I find that higher quality product is best taken from the pressing screen, and put onto glass to dry with air moving around it. I feel that there is too much residual loss when making FMCD to use cardboard.

I have also read recently that the acids from it can leach into your buds or hash, so using cardboard drying boxes is apparently a bad idea unless they are acid free. When making a standard quality bubble that is not too sticky, or not from fresh starting material, you can get away with it. But, like the nugs, the hash taste better and is less harsh when slowly cured. You do want to turn it occasioanly to avoid mold, and keep the air moving. If it gets stuck, the freezer trick works on glass too.

YMMV