This is a subject I know a lot about.
I have a cat who has had the worse time with ear problems.
Just like you described.
Brownish black matter coming out of his ears. I cleaned with everything.
First I thought it was ear mites.
Used the ear mite cleaner for 6 months. Still came back and worse. It wasn't ear mites.
I took him to the vet at least 6 times. The vet thought it was bacterial. So he gave me oral antibiotics and an antibiotic ear cleaner. 10 days later......problem is back.
I received at least 3 other cleaners from the vet. Didn't work.
I used all of these natural “cures” I have seen listed here. Didn't work.
Here is what DID work.
Zymox Otic Pet Ear Treatment with Hydrocortisone (Not the cleaner/wash, but the enzymatic solution)
You can buy it through Amazon. The reviews are amazing. I love it. Best thing I ever bought for my cat that worked.
I used it once a day for 7 days as stated on bottle. Now I use it once every 2 weeks to keep the problem from coming back.
Make sure it isn't ear mites. A vet can tell you. If it isn't....... trust me.....try the Zymox with Hydrocortisone. It will save you money and time.
Ear mites can be gotten rid of with mineral oil or such as that. They breathe through their bodies and it suffocates them.
Great advice. Thanks.