Repair
If your pillow has a hole in it, make sure to sew it completely shut before washing else the hole will likely get bigger and your washer or dryer will be filled with pillow stuffing.
Two at a Time
To keep your standard top loading washing machine balanced, it is best to wash 2 pillows at a time.
If you are only washing 1 pillow, put a folded up towel or two in the washer with the pillow to fill the empty space.
Place the pillows in the washer on their side horizontally and wash them like you would wash clothes.
If you have a smaller washing machine, they might not fit (especially king sized pillows).
Cleaner Options
If your pillows are still not white after washing thems using your usual detergent, here are a few options for cleaners to use.
You may need to wash your pillows multiple times if they are very stained.
Chlorine Bleach
You can wash your pillows in hot water with chlorine bleach and your regular detergent. In order to ensure that the water in your washing machine starts out hot, run hot water in a nearby sink until it turns very hot before starting the washer. If you start a hot water load without doing this, the water entering the washer will initially be cold, then become hot water, so you will end up with the cold water and hot water mixing to become warm water instead of the hot water you need. You can even boil water in a kettle on your stove and add that boiling water to the washer if you desire extra hot water. After the washer has agitated for about 5 minutes, stop the wash cycle for about an hour or two and let everything soak before starting the washer again. Make sure to use an extra rinse cycle when using bleach to ensure the bleach is completely rinsed out. You can even wash your pillows in just bleach then wash them another time using your normal detergent. Keep in mind that bleach tends to weaken fabric, so be careful not to use too much bleach, use bleach too often, or let the pillows soak in bleach for too long.
Borax
Borax, which is hydrated sodium borate, has been used for over 100 years as a detergent booster. Add 1/2 cup of borax to your laundry to aid your regular detergent in cleaning and odor removal. You can use borax with the bleach method above if you desire extra cleaning power.
Powdered Dishwasher Soap
You can add 1 cup of powdered dishwasher detergent to the washer in addition to bleach, detergent, and borax. All 4 cleaners working together should get your pillows ultra white.
Vinegar & Hydrogen Peroxide
Some people like to wash their pillows with a mixture of vinegar and hydrogen peroxide (about 1/2 cup to 1 cup each). Simply mix your regular detergent with the vinegar and hydrogen peroxide and wash in your washing machine with hot water.
Drying
Dry your pillows in the dryer, but add dryer balls or new tennis balls to the dryer to fluff the pillows as they dry.
Do not dry foam pillows in the dryer, hang them to dry instead.
An additional way to whiten pillows is to hang them outside to dry where the sun will bleach them and make them smell fresh.
Tips and Tricks
If you have allergies or sweat a lot, you should probably wash your bed pillows at least once a month.
Use a pillow protector to keep your pillows from getting as dirty.
Many experts believe you should only keep a synthetic bed pillow for 2 to 3 years and a down pillow for 5 to 7 years to ensure good neck support and a good night’s sleep.
Another way to determine whether you need a new pillow is to fold it in half. If it springs open, then it is most likely still good. If it stays folded, then you probably need a new pillow.
Before throwing your pillow in the trash, contact local animal shelters to see if they might want it.