Be aware that the alcohol can be drying, so don't leave it sitting in your pups ears for any length of time, but as a cleaner it is great
16 oz. bottle isopropyl alcohol (70%)
4 tablespoons Boric Acid Solution/powder
17 drops Gentian Violet Solution
Mix all ingredients in the alcohol bottle & shake. (You may need to pour out a small amount of alcohol so it will all fit.) Be sure and SHAKE WELL before each use to disperse the boric acid. It's easier to put in the dog's ears if you put some in a small squirt bottle.
Treatment: Flood ear with solution & massage gently for 60 seconds and wipe with a tissue. Flood a second time and just wipe without massaging. The dog will shake the excess out. The Gentian Violet isn't supposed to stain, but be careful.
I should also add: Do this outside, even though it is not supposed to stain. IT can and does so don't want head shakes going on in the house with it.
I have known many people very very happy with this treatment. My friends Newfoundland had chronic ear issues until she used this stuff. She has not had an issue since. It has been going around the show world for years and years. Many happy people and dogs.

Good luck with it.
Schedule of treatment:
2 times per day for the first 2 weeks
1 time per day for the next 2 weeks
1 time per month thereafter
All ingredients are available at a pharmacy. Even despite the alcohol, dogs don't object to even the first treatment. The Boric Acid soothes the ear & the Gentian Violet is an anti-infection agent. (Where babies get their purple belly buttons from!!) The solution works well on any ear problem from mites to wax to canker. One vet reported a success rate of 95%-99% and felt those not successful had not been routine about it or had not done the treatment long enough. This solution is also effective for the treatment of fungus type infections on the feet & elsewhere on the dog, for cuts on dogs or people, and for hot spots.
For EXTERNAL use only. Avoid getting in eyes.
ONE more thing. You might want to take him to a groomer and have them pull hair out of his ears if the above treatment does not remedy the situation. He might have some little hairs tickling him.