How safe is Ammonia ?

[JasonR]

Hey, I know the caps are probably safe, but I have seen alot of powerlifters with ammonia bottles lately, they just open them and smell the vapor before a lift

I have also seen these bottles of 10% ammonia in the supermarket, which are supposedly for cleaning windows n' shit.

So whats the difference between sniffing a cap and smelling ammonia vapor from a bottle ? is the supermarket ammonia any good ?

thanks