My 10 year-old cat had yellow pus in his ear that led to him shaking his head and turning his head sideways. I treated him with organic Apple Cider Vinegar (with the mother). I used a syringe to administer 1/2 ml of the ACV in his ear. He shook his head and talked to me right after I administered the ACV. He wasn't thrilled about having it placed in his ear, but within two days he stopped tilting his ear and the pus completely disappeared within 3 days. I continued to administer the ACV to his ear for a week and a half to make sure the infection stayed away. A lady I know did the same thing for her dog who was tilting his head and had pus in his ear. She said her dog is doing much better after just two administrations of the ACV. I'm not sure how much ACV she used on him. Her dog is about 45 pounds.
Please exercise caution with this remedy. Apple cider vinegar applied straight can burn and cause terrible pain to a pet. It must always be well diluted in water when applied topically -- at least 50% Water to 50% ACV.