Looking for suggestions on how to remove mildew from OSB.  The house has an attic fan that has let moisture from the humidifier into the attic. The OSB sheathing is growing mold on the underside. I have installed a ridge vent and now seal the attic fan opening during winter months. Any suggestions on how to get the OSB back to its original color. The spores are black not green and my one attempt with bleach did not return the OSB sheathing back to its orginal color as it does when applied to vinyl siding.

Thanks,

Cigar