Mildew odor can linger in the air for a surprisingly long time. Thorough cleaning can help get rid of the unpleasant smell, and ventilating the affected rooms may help as well. You may also find products that absorb moisture and odors helpful. Additionally, you may use dehumidifiers and follow-up cleanings to make sure mildew smells stay away.
To get rid of mildew odor in your home, clean surfaces in the affected area with a solution of bleach and water, and then allow them to air dry. You may also need to dispose of paper or cardboard that may be contributing to the smell and clean or dispose of any fabric in the affected area. Fabric items to which you are not overly attached can be thrown away, but those you want to keep can be laundered. If you have old pieces of upholstered furniture in a room that smells like mildew, your best option may be to get rid of them as well.
Once you've done a thorough cleaning job in the affected area, you may then use ventilation to help you get rid of lingering smells. Open any windows in the affected area and leave them open for as long as possible. If you have screen doors and the weather is reasonably warm, you may also want to leave the doors open for a time. This will not get rid of the odor by itself, but in combination with cleaning, it may help.
There also are many products you can buy to help absorb unpleasant smells, including ones from mildew. For example, you may find products that consist of granules that absorb odors as well as excess moisture in the air. You may also find sprays that are advertised for the same purpose, though some of them may not work as well. Some people also make their own odor-absorbing solution by placing charcoal briquettes in coffee containers or similar receptacles; baking soda may serve the same purpose.
Once you have managed to get rid of mildew odor, you will likely want to make sure that it stays away. Repeat the cleaning of the affected area periodically to ensure the mildew doesn’t come back. A dehumidifier can also help keep mildew-causing moisture out of the air.