Peroxide vs. bleach?

My grandmother used it as mouthwash for many years - more to prevent cavities than whiten, although I've heard it will help with stains as well. When she died she still had a good strong set of teeth and they were all her own. I myself can't get past the taste of it but thankfully they now put it in toothpaste. I refuse to buy toothpaste unless it has baking soda and peroxide in it and the last time I went to a dentist (I don't go very often) he and his nurse were amazed when they found out how long it was since my last visit/cleaning. So I guess it works. All that other stuff you mentioned I can believe. However I think I would feel like I was drowning if I sprayed it up my nose. ( A Little salt water works for stuffy nose also.)