Typically associated with the aroma of a basement, musty smells can occur on cushions when fungus is present or when stored for long periods of time. No matter what the cause, the musty odor will turn the cushions into a stinky mess. Since cushions are typically not machine washable, you must deal with the unpleasant aroma by hand. Fortunately, an all-natural and inexpensive product will eliminate the musty smell without filling your home with chemicals.
Check the cushion's label for the manufacturer's recommended washing instructions. Remove the cover -- if the cushion has one -- and launder according to the label.
Examine the cushion and -- if mildew or mold is present -- hang the cushion outside on a clothesline. Apply an aerosol fungicide to both sides of the cushion. Air dry for several hours.
Cover a flat surface with a towel. Lay the smelly cushion on top of the towel. Add undiluted white vinegar to a spray bottle.
Mist the top side of the cushion lightly with the vinegar. Let dry. Flip the cushion over and mist the bottom side. Let dry.
Repeat the process as often as needed until you have eliminated the musty smell.