Any danger to leaving brown sugar exposed to air? Yesterday I went to check if I had brown sugar for a recipe and found that my bag, which comes with a zip lock, was totally unzipped I am guessing for months.  Any danger here or should it be ok?  I am guessing it's just for convience and to prevent spilling but curious if anyone has any knowledge.

It's "dark" if that matters.

NOTE: I am aware it probably dries it out faster and causes it to become hard but I consider that just a general thing with brown sugar and not a danger=)
Since you wrote that it dried out, I would check for two things:


insects;
mold on the surface - but I consider that unlikely.