If any type of dry ingredients are wet or stored in a damp places this could cause bacteria to grow. And not the good kind. Compare it to a food product like flour, if you dropped a bag in the sink, you would not just store it as is, wet, it would mold. Spreading it out and drying it should save most of it. I keep my guano in plactic tupperware and in plastic inside the tupperware, mostly to avoid breathing any particles but it keeps the moisture out too. Treat your organic ammendment like dry food when storing, to keep them from degrading.