Wear gloves, an N95 or better respirator, and eye protection
Stop the moisture source before cleaning
Ventilate the area
Isolate the affected space with plastic sheeting if needed
Remove and discard drywall that is soft, crumbling, or heavily mold-damaged
Clean small, non-porous areas with detergent and water
Wipe the surface dry completely
Apply a mold-killing product approved for drywall surfaces
Scrub visible mold with a stiff brush if the drywall is still structurally sound
Dry the area thoroughly with fans and dehumidifiers
Replace insulation or materials that were contaminated
Seal repaired areas with mold-resistant primer and paint
Monitor for recurring moisture or mold growth
Call a professional for large areas, hidden mold, or sewage-related contamination