Vinegar helps to remove stains and disinfect.
Dark liquids, as well as liquids containing fat or oil, can stain bottles. If you want to use the bottle, you'll want to make sure that it is sanitary and free from stains. Even if you don't plan to drink out the bottle, you'll want it to look clean if you plan to display it. You can clean bottles easily with a gentle, homemade cleaning solution.
Soak the bottle in a mixture made of equal parts hot water and white vinegar.
Squirt several drops of liquid dish soap onto a clean, damp bottle brush and use it to brush out the inside of the bottle. Squirt the dish soap on a cloth to wipe off any remaining stains on the outer portion of the bottle if necessary.
Rinse the bottle well and place it on a drying rack to air dry.