Cleaning
infested material

Remove mould only with a vacuum cleaner that contains an HEPA (high effciency particulate air) filter capable of retaining 99.97% of all particles down to 0.3 microns. Conventional vacuum cleaners have drawbacks: often the suction is too strong; as the bag fills up the efficiency decreases; the exhaust can be contaminated with fine particles not trapped by the bag, therefore redistributing them around the room. An HEPA vacuum cleaner is an effective way to remove mould because it does not spread the spores around. Vacuum cleaners designed to filter air through water are unsuitable for capturing mould’s small particles. Even if a fungicide is present in the water, this will not prevent particles of mould from being discharged back into the air.

While certain treatments can kill mould that is active, they are far less effective with dormant spores, which are protected by relatively impervious cell walls. Proper conditions will insure that dormant fungi remain inactive and will prevent germination of accidentally introduced active spores. If the environment is favorable to fungal activity, mould will grow. Even if complete eradication were possible, it would not be a permanent solution in storage spaces without climate controls. More spores are always being introduced and would sooner or later become a problem.

If it is not possible to remove mould outdoors, work in front of a fan, with the fan blowing contaminated air out a window, or work in a ventilation hood. Make sure the ventilation hood uses a filter that traps mould. Be sure to remove the mould in an area well away from collection storage and other people. Close off the room. If the building has central/mechanical air circulation, block the uptake vents so that spores are not spread through the building via the air-handling system. Take care when disposing of solid cleaning materials such as vacuum cleaner bags or filters. These should be sealed in plastic bags and removed from the building.

To remove inactive mould from paper or books, use a multiple-filter vacuum cleaner (see above). Small brushes and nozzles used for cleaning computers are useful for this purpose. Papers can be vacuum cleaned through a plastic screen held down with weights. A brush attachment should be used for books. Covering the nozzle or brush with cheesecloth or screening will guard against loss of detached pieces. Remember active mould is soft and subject to smearing, and is easily rubbed into porous materials such as paper or cloth.

Active mould is best removed from valuable artifacts with a small low-pressure vacuum cleaner.

When fungal growth is visible on art objects or valuable items, it should be removed by a conservator. Staining caused by mould can often be removed or at least lightened. This is an expensive procedure and therefore most suitable for objects of significant value.