From Kodak <
http://www.kodak.com/> publication AE22
REMOVAL OF FUNGUS FROM NEGATIVES AND SLIDES
You can remove most surface fungus from negatives and slides by gently wiping them with a KODAK Photo Chamois, a soft plush pad, or absorbent cotton moistened with film cleaner. DO NOT USE WATER OR SOLUTIONS THAT CONTAIN WATER to remove fungus, because fungus growth usually makes the emulsion water-soluble.
Remove slides from cardboard or glass mounts before you clean them. Clean the film and glass mounts and place them on a piece of window glass to air dry. To accelerate drying, warm the window glass by mounting it a few inches above a low-wattage light bulb. After approximately 10 minutes, you can remount the film in clean glass mounts or new cardboard mounts. Wear clean cotton gloves to avoid getting fingerprints on the film. DO NOT DRY FILM UNDER HIGH-INTENSITY LAMPS OR IN SUNLIGHT.
Note: There is no satisfactory method for complete restoration if fungus growth has etched or distorted the film emulsion.
REMOVAL OF FUNGUS FROM PRINTS
Fungus growth will appear as dull spots on the surface of prints. You can usually remove these spots by wiping the prints with film cleaner as described above.
If fungus damage is minimal, you can have a copy made, and retouch it. If fungus damage is extensive, the emulsion layer will strip off the print, and restoration is usually not possible. Discard the storage containers in which the damaged prints were stored.