I recently made a discovery that made me think my nail fungus had improved by 80% overnight! I'd been rubbing clove oil on one of my big toe nails for a couple of weeks. Then one night I decided to add coconut oil an hour after applying the clove oil. The next morning it looked as though the fungus had all but disappeared. I was thrilled! But, ha ha, it was temporary. As soon as your feet get wet, the nail returns to its previous state. I switched to shea butter (100%, cheap) because it lasts even longer than the coconut oil (from shower to shower). Not sure how effective this will be for black-ish nail fungus as mine is a lovely white & yellowish swirl.
So for everyone who is currently wearing open-toed sandals this summer, you might want to try rubbing coconut or shea butter to your infected nails. It's a helpful tool while we battle this pain-in-the-you-know-what condition.