Wear gloves, an N95 mask, and eye protection
Ventilate the area
Fix the moisture source first
Remove and discard any moldy insulation or damaged drywall that is soft, crumbling, or heavily stained
Lightly mist the moldy area with water to reduce dust
Clean the surface with soap and water
Wipe with a mold-killing solution such as diluted vinegar or a commercial mold remover
Avoid soaking the drywall
Scrub gently with a soft brush or sponge
Dry the area completely with fans and a dehumidifier
Sand lightly only if the drywall is dry and the mold is superficial
Prime the cleaned area with a mold-resistant primer
Repaint with mold-resistant paint
Replace drywall if mold returns or if the damage is extensive
Dispose of contaminated materials in sealed bags
Wash hands and clean tools after finishing