Cleaning a dog's ears?

My dog is a lab/mastiff mix, 5 years old. We got him from the pound 3 years ago, and he has a chronic bacterial infection in his ears. We have tried the most powerful antibiotic on th emarket, drops and oral, yogurt, garlic, vitamins, cleaning daily, etc., and nothing has worked. I am wondering if anyone has any suggestions for solutions for cleaning out his ears. We are currently using half apple cider vinegar and half distilled water, but this only seems to work when we use it daily, and I hate putting my dog through that. Any help would be greatly appreciated! Thanks.