Covid-19 virus and other flu-like viruses lives in the back of nose area. The reason for this is because it is one of the coldest parts of the body due to being made up with mostly cartilage and little muscle to produce heat or insulate. Covid-19 virus has a lower chance of survival in higher temperature, and targeting the nasal cavity area with high temperature and moisture over a continuous period of time will kill off a high percentage of the Virus.
The easiest way to do so is to boil a pot of water, add citrus fruit peels(easiest), and breathe in the steam from the boil for 10-15 minutes. Alternatively, you can add lemongrass, ginger, and squeeze in lemon or lime juice.(remedy many Vietnamese use to combat cold and flu virus) Additionally, you can also visit the sauna, but I can't imagine any opened right now due to the shut down. Keep the pot, and reboil again every 1-2 hours and breathe in the steam for 15 minutes, and symptoms will decrease within 2-3 days. Just want to share a natural remedy that my family and I have been using for years, thanks for your time and hope this helped!