Fill a bathtub or large sink with hot water. Add the amount of mild laundry detergent indicated on the back of the specific container.
Submerge the stained pillow in the hot water completely.
Press the pillow together while it is under the soapy water a few times so that it completely absorbs it.
Allow the pillow to sit in the hot soapy water for 10 minutes.
Scrub at any surface stains on the pillow with an old toothbrush, using small circular motions to break apart and lift away the marks.
Drain all the soapy water and refill with clean, hot water. Press the pillow together a few times while under the water to help rinse out any lingering detergent.
Repeat the rinsing process three or more times, until there is no trace of the detergent in the water.
Press the soaked pillow in between a clean towel to remove excess water.
Hang the pillow and allow it to air-dry. You can also place the pillow in the dryer with a few tennis balls to help fluff it back up.