I'm stumped as to how to fix or clean this. I'm not sure if it's mold or just condensation from the windows (they get fairly wet as the sun rises and I think the evaporation creates moisture that rises up to the ceiling) and dust sticking to it. It's also possible that this is a carry-over from when the roof collapsed and was "fixed" by the previous owner.

Regardless of what it is, I can't seem to figure out how to clean it or prevent it from happening again. Wiping it with anything, dry, wet, with various substances (I've tried a bunch of stuff like vinegar, sugar soap, etc.) just smears it and dirties the ceiling even more. It's an unpainted ceiling so I figure that's not an option unless I paint the entire thing and even then, wouldn't I need to get rid of this stuff beforehand anyway?


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