For what it's worth in my short time with the hobby (a couple years) the only mold I've seen is with a cigar jar where it's very air tight, and that's with opening the jars once a week for a little bit to let some fresh air in, but not shuffling the cigars around. I find that it's so easy to nick the wrapper on cigars that don't have cello so I'm hesitant to move things around a whole lot.