https://www.americaoutloud.com/dilute-povidone-iodine-nasal-oral-washes-for-the-prevention-and-treatment-of-covid-19/
More discussion about this nasal wash is on this video.
https://freeworldnews.tv/
Start at 1:24:35 for beginning of that part of the discussion.
Of course, if you have children in the house, whether your own or visitors, you want to keep the iodine away from them, as too much is toxic.
Dr. McCullough gives a formula for dilution.
His site is https://americaoutloud.com