I suppose you could, but if there was moisture retained in the packet could it mark the card ? I forget if the packets are papery or a plastic. You could try taping the packet to the inside of the case, so its above , I don`t think I`d put it resting on the bubble Incase.Chaps,
Can you put small silica gel packets in acrylic display cases with MOC figures??
Looking into a solution for mold.