Dogs' ears are perfect areas for bacteria and yeast to live. This is a problem especially for dogs with floppy ears. Ear infections can eventually be quite serious, but mild cases can be solved and then prevented by cleaning your dog's ears with a simple homemade wash.
Mix 1 part white vinegar to 2 parts water for general cleaning. If the dog has an active infection, mix the witch hazel, gentian violet, and boric acid powder and use this as the wash.
Shake the solution well before each use.
Apply the wash outdoors or in a bathroom. Washing dog's ears can get messy, and gentian violet can stain.
Dip a clean cotton ball into the wash, squeeze out the excess liquid and apply to the ear. At this point, the dog will probably shake his head to get rid of the excess liquid in his ear. This is okay.
Dip the end of a cotton swab into the solution. Apply the swab very carefully to the narrow parts of the ear, but don't go in too far.
Repeat this cleaning ritual every day for active infections, and once a month for general cleaning.