[T.G]

I would just use some water and let it dry, then maybe sand it lightly. If you try to neutralize it with vinegar or some other acid, you've started playing a guessing game as to how much acid is needed, you could easily end up swinging the scale the other way. Also, something like vinegar could introduce an odor into your humidor that you might not be able to get rid of.

So long as the cigars were not in direct contact with the chemical, for as large a volume space as the humidor is, and how little was actually leaked, I doubt that you have anything to worry about.