What is the best way to dry out our attic. While putting away Christmas deco I noticed black mold on the ceiling. We don't have the money to pay a professional to get rid of it. And with the cold weather it isn't drying. We stopped using the bathroom vent which put the moisture in the attic in the first place. I just need some info on how to get it completely dry before we start to get rid of the mold. The bathroom vent is now going blowing outside..this is a big mess no leaks from the roof just from the moisture from the fan.
If you can get to it, try spaying it down with a diluted bleach solution. Then see if the dry winter weather kills it off.
You may have already removed its source of moisture and depending on how much there is it may die off on its own.
You should check it periodically to make sure it doesn't get any bigger.
As ArchonOSX mentioned, you can spray bleach solution on the mold. After they are killed off, use lemon salt + water solution to prevent future mold problems. Remember, after applying lemon salt solution to the surface, you will not be able to paint the surface (if you need). The better solution to prevent mold growth while saving energy is to use rock wool or other kinds of insulation materials for attic insulation. Insulation will not cost too much if you apply it by yourself. There are lots of information on the internet about how to do it.
Now that you're resolved the problem (the misplaced bath fan exhaust), it'll dry up on its own. Any airflow you can provide helps, as would a dehumidifier or a moisture-absorption product such as DampRid.