If mildew growth is a problem, prepare the following solution to clean and sterilize:
3 qts. warm water,
1 qt. household bleach(clorox)
2/3 c. tri-sodiumphosphate or borax
1/3 c. detergent (Tide)
Mix thoroughly and it's ready to use. Scrub affected areas and rinse throroughly and allow to completely dry. Painting should follow asap to prevent surface reinfection.
During preparation and cleaning wear rubber gloves and eye protection. If eye or skin contact occurs, flush immediately with plenty of water. In case of eye contact, also consult a physician.