Use a spot-on treatment containing selamectin or moxidectin. Selamectin and moxidectin are ivermectin (a broad spectrum anti-parasitic drug) derivatives and have shown to be specifically effective against ear mites. These are both prescription products, and will thus need to be supplied by your veterinarian. Their mode of action is to disable the parasite by interfering with their nerve conduction. This results in paralysis and eventual death of the mite.