"ransley" wrote

Bleach kills mold by removing oxygen to the plant, vinegar might be
food for it. Spray the infected area with alot of bleach completely,
its cheaper than vinegar also. If its inbetween walls , drill holes
and use a garden sprayer.

Are you sure the drilling holes and spraying is safe? He's apt to have
electrical cables back there and bleach can damage the coatings.