Put on gloves and a mask; ventilate the area
Remove items from the area and contain the work area with plastic sheeting if possible
Dry the wood as much as possible before and during cleaning
Vacuum loose mold with a HEPA vacuum (do not use a regular vacuum)
Use a stiff brush to scrub mold off the surface with dry brushing motions
Wipe the area with clean water to remove loosened residue
For non-porous/sealed wood: clean with detergent and water, then disinfect with a solution such as 1 cup bleach per 1 gallon of water; keep it wet for 5–10 minutes; scrub; rinse with water; dry completely
For porous/unsealed wood: clean with detergent and water, scrub thoroughly; rinse lightly; dry completely; if staining or mold persists, sand the affected layer and remove dust with a HEPA vacuum
For stubborn mold: use hydrogen peroxide (3%); apply, keep damp 10–15 minutes, scrub, rinse, and dry completely
For mildew on unfinished wood: wipe with white vinegar (undiluted), wait 1 hour, scrub, rinse, and dry completely
Do not mix bleach with vinegar or other cleaners
Dry the wood fully using fans and dehumidifiers; continue until no moisture remains
Dispose of contaminated rags, brushes, and vacuum contents in sealed bags
Repeat cleaning if mold returns; address the moisture source (leaks, humidity, condensation, poor ventilation)
If mold has deeply penetrated, the wood is soft/spongy, or the affected area is large, replace the affected wood or consult a professional