Spring break or New Year’s Eve parties do not always finish as well as they started, as well as some dinners in tropical countries. In this case you may have to remove some vomit stains.
If the stain is recent, remove as much of the vomit as you can with a spoon or spatula and rinse with warm water
You can also dab these stains with a cloth dampened with diluted ammonia. The ammonia might damage the cloth, so it’s important to dilute it a lot at first and to test the mixture by dipping an ear bud in it and trying the concentration on a hidden part of the cloth/garment, such as the hem. If the ear bud is tinted by the dye in the fabric, or the fabric is damaged, dilute the ammonia further.
Or dab the vomit stain with a cloth soaked in hydrogen peroxide.
On a woollen fabric, water mixed with white vinegar is preferred.