You need to have well sterilized water for that just not to lead to a sinus infection which will leave you more susceptible. Tapwater isn't good enough, and is

You need to have well sterilized water for that just not to lead to a sinus infection which will leave you more susceptible. Tapwater isn't good enough, and is going to be rather harsh out of most taps in the US. Clean water in general isn't a solved problem. If you decide to do this with tap water, leave it out for a day or so to let the chlorine evaporate and then boil it for at least 5 minutes. Netti pots are also basically waterboarding fyi. Have fun!