Upon inspection, I have some of this mildew inside one of my nuc boxes. The bees seem like they are fine for now. Once I move the bees to larger box when it is warmer, I wanted to ask what people use to clean this out. Worried diluted bleach will clean it, but leave a smell the bees won't like. Thought about soapy water, but wasn't sure about residual smell either. TIA for letting me know what you have used in the past.
As I understand it, the bees will clean that up. It caused by a lack of airflow in the hive and too much moisture. Leave the bees in there and they will clean it up.