A Guide to Long-Term Clone Storage, 2+ Months, And a Continued Experiment to Reach 6+ Months

Can someone tell me what are the essential conditions for long-term storage of clones? Clearly, apart from the absence of mold and other pathogens. Air, temperature, humidity…
I just read about chlorine dioxide. Gas that is heavier than air, easy and cheap to make, sterilizes and kills bacteria, mold…
Perhaps it could be put to good use in the preparation and preservation of clones.