Adie, in my case, after suffering with multiple sinus infections, year after year, for decades, I experimented with flooding my nasal passages with a mixture of diluted 3% hydrogen peroxide, baking soda and kosher salt. In order to flood my nasal passages and keep them flooded, I keep my forehead pointed downward. I keep my forehead down for quite a while, hoping that the anti-infective mixture can get to the infected area(s) within my sinuses and nasal passages.
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It works! I have been sinus infection free for about 3 years. I think that I had chronic infection problems with my turbinates, so flooding my nasal passages with the anti-infective mixture worked very well, for me, since the infected areas were fairly easy to reach.
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To read the documentation, and an actual Log of one of my flooding experiences, follow the following link: