Unlike cats, dogs need to be given a bath about once per month. Dogs don't naturally clean themselves and need a bath to get their fur clean. You can spend the $4 to $6 for a store-bought dog shampoo, or you can make some at home for less than $2. Many homemade dog shampoos require you to use glycerin, but it is not necessary if you use the right ingredients. Wash out an old shampoo bottle and let it air dry. Fill the shampoo bottle 1/3 of the way with vinegar. Add liquid Ivory antibacterial soap until the bottle is full. It must be Ivory soap because the pH balance must fall between 6.2 and 8.6 for dogs' skin to stay healthy. This amount of Ivory mixed with this amount of vinegar brings the pH level to 6.8. Other soaps would have a different pH balance. Shake the bottle so that the two ingredients are combined. Place a sticky label on the shampoo bottle and write your dog's name on it. This will ensure that no one else in the family accidentally uses it.