If you find yourself in a situation where you have moldy upholstery, then there are a few courses of action. If it is light mold, caused by leaving wet clothing on a sofa, or leaving a wet area to remain damp, then you can usually brush the mold off, because it won’t have started really embedding itself in the fibers. If you have heavier mold then you can try applying stronger methods of mold removal, which will be detailed more thoroughly below. However, with upholstery, the instances that mold can grow are usually ones of serious neglect, or storage in damp conditions. Unfortunately, you may be fighting a losing battle, and the only answer to a sofa or arm chair that has a really bad case of mold is to throw it away, as there is little that you can do about the holes and stains that heavy mold will cause. Bringing heavy mold in to the house from a storage unit is a sure fire way to get mold spreading around the house, so be careful with what you do bring in to the house, and ensure that everything is checked thoroughly and cleaned properly before you do so.
You will find that aside from the physical process of brushing, the best things to use to get rid of mold are those that will kill the live spores that cause the problem to grow. You will find that these things can be anything from laundry soap to bleach, and there are many things in between. You should start off with the milder chemicals instead of using the harsher ones, as the risks associated with things like bleach are much higher and much worse if things go wrong. Some materials used in upholstery are actually not ok to mix with certain chemicals like bleach, as they can be broken down physically by them, or stain them further. You will find that the best way to apply these chemicals is with a simple flannel or sponge, but if you are using harsh chemicals like bleach, then be sure to wear gloves to avoid contact with the skin.
Laundry soap simply lathers up in to a foam, and you should scrub away at the stained area, allowing the soap to do it’s job. You will need to avoid soaking the area, as that will give you a much higher risk of the padding beneath the affected area getting damp and not drying out, which can result in further damp and therefore more mold! Using hydrogen peroxide, vinegar, lemon or bleach will give you a water free process, as you don’t need to rinse them out like you do a soap, a little dilution will be enough, as these chemicals will dry up much more quickly. You will no doubt find that the combination of these compounds and a little agitation will relive the stain a fair bit, so keep washing the area, and checking back to see if the staining has gone or not.
If you can, dry the affected area in fresh air and sunlight, as this will allow the UV rays of the sun to further bleach the mold away. You should find that the cyclical air will prevent the water used in the cleaning process from soaking in to the padding as well, and is a good way to prevent the further damp as mentioned above. In an ideal world, every sofa would have a removable cover that you could boil wash, but if yours don’t, and you have no joy from the options mentioned above, then you may need to call a upholstery cleaning company.