Chocolate stains are notoriously tough to get out of clothing, and chocolate milk is no exception. Although it's ideal to catch stains as soon as they occur, it's still possible to remove a stain after it has dried on your clothing -- that is, if you're willing to try multiple techniques to get the job done.
Soak your stained clothing in cold water for several hours. Use a bucket or large bowl so it can remain undisturbed. Boost the soaking power by adding baking soda or oxygen cleaning powder to the water to help loosen the stain.
Pull the soaking clothing out of the water and add a few drops of dish soap directly on the stain. Scrub the fabric between the knuckles of both hands, frequently dipping the material back into the water to rinse away loosened particles. If scrubbing with your hands isn't working well enough, use an old toothbrush to scrub directly on the stain with dish soap.
Rinse and wring out the article of clothing and spray stain pretreatment spray directly on the stain.
Wash the clothes in a washing machine with regular laundry detergent. Add color-safe bleach for brights or darks, or standard bleach for white clothing. You may also want to add baking soda or an oxygen cleaning powder to the wash cycle.
Check the stain as soon as the wash load ends. Repeat Steps 2 to 4 until the stain is gone.