Mildew smells most commonly indicate a presence of mould growth. If you try to remove mildew smells with chemical air fresheners or perfumes, you will only make the situation worse and the underlying mould will continue to spread. In order to remove the musty mildew smell, you must remove the source of the smell. Older homes and previously flooded homes are particularly susceptible to mildew odours, but small leaks can also produce a musty smell.
Examine your home for signs of water leaks or water damage. Common sources of leaks are basements, roofs, faucets or pipes. If you see fuzzy discoloured growth around water stains, you likely have mould growth resulting from those leaks. Use a flashlight to help you see behind or underneath objects and into dark closets or cabinets.
Fix any leaks or water damage. Depending on the amount of damage, you may need to contact a plumber or contractor to repair the leak and damage. If you find evidence of active mould growth, a professional is your best bet to remove it completely.
Use fans in the bathroom and kitchen. These areas of the home produce quite a bit of humidity, which can worsen mildew smells until the source is removed.
Keep floor mats in the bathroom and kitchen dry. Wash them regularly, and avoid wall-to-wall carpeting in these areas.
Use a dehumidifier or air conditioner to lower the overall humidity in your home. If you do not use your central air conditioning very often, have a professional come and inspect your air conditioning system to ensure that it is not leaking and is operating properly.
Discard any mildewed or mouldy items that cannot be cleaned. If items can be cleaned, use a mixture of equal parts bleach and water to ensure that you kill the mould spores.
Freshen the air after you remove the source of the mildew. Use small bowls of white vinegar in any rooms that still have a musty smell. The vinegar neutralises remaining odours without adding chemicals to the air in your home. Leave the bowls out for several hours or until all lingering mildew smells have disappeared.
If the humidity levels outside your home are lower than the humidity inside, open your windows to allow fresh air in.
Use eye protection and gloves when cleaning with bleach. Keep bleach away from children and pets.