Vinegar is a great cleaner for water-soluble stains and can also remove coffee. According to Reader's Digest, as much coffee as possible should be blotted up with a moistened towel. Next, the spot should be patted with a towel freshly moistened with undiluted white vinegar.
After applying the vinegar, the item should be put in the washing machine. Soaking overnight is an option for larger stains. Three parts vinegar can be mixed with one part cold water prior to washing. If a washing machine is not readily available, the vinegar can be applied with a dry cloth and blotted. There is no need to rinse out the vinegar with water. When completely dry, the coffee stain is gone.