Mildew thrives in damp rooms that aren't aired regularly. Removing the musty smell of mildew from a mattress that's been left in a damp room is possible, but it takes a bit of elbow grease to get the job done. Try this simple treatment to remove mildew odour from a mattress easily and inexpensively, before you call in the professional cleaners.
Take the mattress outside, if possible, and brush it with a soft brush or broom to remove any loose mould or mildew from the outside surface. If you're unable to move the mattress outside, wear a face mask to prevent inhalation of mould spores.
Move the mattress back indoors, and vacuum the surface area with an upholstery attachment. This will remove mildew and mould from deeper down in the mattress fabric.
Combine 50 ml (1/4 cup) of washing powder with 500 ml (2 cups) of warm water in a small basin. Swish to combine, and dip the sponge or soft cloth in the solution. Apply gently to the surface, covering the entire mattress or the smelliest parts.
Fill another basin with clean, cold water and blot the soap from the surface of the mattress with a clean sponge or cloth. Rinse and wring out thoroughly between blotting.
Use an electric fan or hair dryer to dry the mattress completely after washing. Open windows and allow the sun to shine in, if possible, to speed up the drying process.
Spray the mattress with a fabric refresher such as Febreeze, or a generic equivalent, once it has dried completely to eliminate any lingering mildew odour.
Try to get as little water as possible on the mattress while applying the detergent solution and cool water. The object is to gently clean without soaking the mattress pad or filling, which could lead to further mildew formation.
Do not place the mattress in a dank, damp or humid area while wet, or more mildew may form.