Re: It has been tested already!
The only method I can think of is by transferring good lip bacteria from someone without EC onto someone with EC, via kissing, or swabbing lips and transferring. Probably the most effective through kissing.
Everyone starts off with good bacteria on their lips, but after losing it, it doesn't seem to come back on its own. The reason I think the moisturize method didn't work for anyone else other than Daniel Miller is because he had good bacteria on his lips (from kissing) and then the moisturize method allowed the good bacteria to grow and multiply. He had no results from the "keep it dry" method because the bacteria had no moisture to grow. The moisturize method does not work for anyone else because no one else has any good bacteria on their lips to moisturize.
Unfortunately, while my theory and solution sounds simple, kissing someone is probably the hardest thing someone with EC can do. You can't simply buy something and apply it. You have to actually interact with another person, get a boyfriend/girlfriend or find someone to kiss and possibly have oral sex with (as White Shark suggested).
That is the main reason why I can't test my own theory. Actually trying it is the hard part. I have never had a girlfriend in my life without EC, so I sure as hell can't get one with EC. If someone is outgoing, unlike me, I was thinking you could try something like tinder to find someone to kiss and have oral sex with (as White Shark suggested). Isn't that what people do on tinder?
I still think my theory will work or is worth trying, especially for people who have had no benefits from diet changes, moisturize method, and have no allergies, yet still have EC.