Remove pillowcases and check the care label first. Most polyester and down-alternative pillows are machine washable, but memory foam pillows usually are not.
Fill your washing machine with hot or warm water and add:
½ cup baking soda
A small amount of laundry detergent
1 cup white vinegar during the rinse cycle
Wash two pillows at a time to keep the machine balanced.
For yellow stains or heavily soiled pillows, pretreat with a paste of baking soda and water or a stain remover before washing.
Run an extra rinse cycle to remove all detergent and odors.
Dry thoroughly on low heat with a couple of clean tennis balls or dryer balls to fluff the pillows and prevent clumping.
To leave pillows smelling fresh, add a few drops of lavender or lemon essential oil to a clean cloth and toss it in the dryer for the last 10 minutes.
Make sure the pillows are completely dry before putting pillowcases back on to prevent mildew smells.