I would remove the cigars right away if you're sure it's mold. Like kombat said, check the cigars for mold.
Do you know where the RH is? Is it high? If it is, let it stay open for a day.
Once you're sure the box isn't over saturated, wipe it down with rubbing alcohol. Don't soak it with the stuff, just lightly apply it making sure you miss nothing. Then keep it open for another day.
After that, slowly bring it back up to the 65-68 RH range. With your cigars in it is fine.
I'm no veteran, but I went through this with a brand new humi just a few months ago. Only, I bought it from cbid and it arrived with mold. Returned that one, and the second had the same problem so I just decided to correct it myself. Worked great.
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