I was happy to include the last notebook together with his parents, grandparents and more. The family grows. I used to keep then inside a fireproof and waterproof box since they are treasures. I always remember the fire in Peter Beard's house and the lost of many years of notebooks. Tragedy.
However while trying to protect my notebooks I was putting them into a high risk. I know now these kind of fireproof boxes are not recommendable for humidity reasons. Indeed, I did some tests tracking the moisture inside and... surprise! The humidity increases even when it's empty and filled with room air (to discard the possibility of humidity caused by the items). It comes from the wall box, materials which contain water or something similar. Fortunately I keep a silica gel bag inside and the damage was not so bad, I hope.
It looks like keeping the notebooks safe from fire will have to wait until I discover a solution.