Don't waste money and chance accidentally buying a cleaner that will dull the color of paint on your wall. Use this inexpensive, old-fashioned recipe that people have been using to attack pesky stains on painted walls for years:
Mix 1/2 cup vinegar, 1 cup clear ammonia, 1/4 cup baking soda and 1 gallon warm water. Apply to the wall with a sponge and rinse with plain water. Because this cleaner contains ammonia, you should wear rubber or vinyl gloves when applying it and make sure the room you are working in is well ventilated. Your walls will be spotless without the risk of becoming dull.