I was curious about why not to use plastic. One of the people replied to me about collidal silver and told me to use it in a nasal sprayer, so I did. They didn't tell me not to use it in plastic. Exactly what is collidal silver. I was using it for 2 weeks and noticed a big difference in my breathing, I have asthma, and in my sinus symptoms too. Could you explain a bit why not to use the plastic? I don't know what else to put it in to spray my sinuses.