This is a somewhat urgent matter that’s been gnawing at me for some time.
Since I acquired my first Civilian General Respirator, I’ve stored it for long periods of time in different places, in and out of its canister. I’ve noticed that over time, it has begun to crack and perish. Obviously not a good thing!

My question would be: In what sort of conditions should I be looking to store these masks?

I should note that my collection room, which is also where I sleep, is not temperature controlled. There is no way for me to physically stabilise the temperature or humidity in the open space, and in summer it can get very muggy indeed.
In my display cabinet, where I have several masks displayed, I use disposable dehumidifiers placed on the bottom shelf. Would these harm the rubber in the long term, or is that a good move?
None of my masks are exposed to direct sunlight, and are either behind glass in the cabinet or up on a shelf in their boxes and bags. I also have a couple under my bed, in a cardboard shoebox stuffed with acid free paper. I have treated some of the poorer examples with Renaissance Wax to try to prevent further oxidisation.

Is there anything more I could or should do to preserve these items? I’m at the end of my tether as far as this goes, and help from those better versed would be greatly appreciated!

Best regards, B.B.