Eliminate the source of moisture. Leaking plumbing or inadequate ventilation in humid areas, like bathrooms or laundry rooms, must be addressed. Wipe up any standing water.
Put on your gloves, respirator mask and goggles. Remove mold from hard surfaces using all purpose, household detergent and water. A good detergent solution is 1/4 to 1/2 half cup detergent per gallon of water. Soft surfaces, like carpet and drapes may need to be discarded. Scrub thoroughly, using a brush if needed.
Apply a bleach solution of 1 tbsp. chlorine bleach to 1 gallon of water to colorfast, hard-surfaced areas. Apply to a towel and wipe down, removing all visible mold that remains. Dry thoroughly.
Remove the moisture and humidity in the affected area. Proper ventilation is a must. Dry thoroughly, using a fan or dehumidifier if needed. Ideally, water and moisture should be eliminated within 48 hours to inhibit mold growth.