It does have anti-fungal properties and may be useful for cleaning up small areas of mould before it takes hold and spreads too far.
Generally, a ¼ of a teaspoon of oil of cloves to 1 litre of water is sufficiently strong to kill mould on most surfaces. You will need to leave it overnight.
To be truly effective on porous surfaces the oil will need to penetrate to the core fibres and this could cause problems with staining for delicate fabrics or carpets.
As always it pays to spot test on an obscure corner before cleaning the entire surface.
After 24 hours you should clean the oil off with a mixture of baking soda and white vinegar. Oil of cloves will work on many surfaces including glass, tiles, steel, enamel, and sealed timber but is not a good choice for fabrics.
Another major problem with clove oil is that it may release a potentially harmful vapour: eugenol. Eugenol is potentially toxic to the skin, eyes, liver and may trigger allergic reactions in some people.
To sum up:
Oil of cloves is a useful substance to have around the home. It is a bit fiddly and messy to use.
It will help clean up light mould infestations but you really need to call in the experts to identify any serious hidden moisture problem and to eliminate all the mould spores so the mould won’t come back.
Oil of cloves is just not adequate for dealing with serious mould problems.