The whole leaf shipped by WLT usually comes in sealed bags. Their poly-nylon bags are entirely vapor-proof, and their heavy gauge polyethylene bags are nearly so. It is sealed within the bags at medium case (fully pliable, but not damp) at controlled, warehouse temperature—like a typical home. If the sealed bag is shipped or stored at a significantly lower temperature, the internal relative humidity will increase.
These shipping bags should be carefully opened with scissors, cutting a clean line across the seal at the top, so that the top edge can subsequently be rolled, flattened and clamped, to retain humidity. Each time the bag is opened, for inspection, or to remove some leaf, the humidity of its contents drifts toward that of the room environment in which it is opened. If the ambient environment tends to be more humid, then the leaf’s moisture content may increase toward it. If the ambient environment tends to be drier, then the leaf will gradually dry.
If the leaf in a container becomes too moist (risking mold), that can be reduced by gently warming the open bag, to drive off some of the excess moisture, then sealing the bag again. If the leaf is too dry, its contents can be lightly misted with non-chlorinated water, then sealed again. Light misting will disperse its humidity into all the leaves in the bag over a period of a few hours to a day.