Second bit on Silca Gel or equivalent clay based product. DO be careful with reheat if the product is in porous paper bags with glued seams. Had a shipment of product where the seam glue softened during the reactivation bake. Very hot granular and dirty surprise when we picked them out of the lab oven.
Silca Gel and clay products act to balance the humidity, If moisture is needed at a certain percentage then the properly 'damp' bag will dispense moisture until equilibrium is reached just as the 'dry' bag will absorb until equilibrium is reached.