Originally Posted by Coldgr33ntea
For the metal to give off those fumes it would first have to reach its melting point, then its boiling point. Unless you see pieces of molten metal in your bowl after smoking it, you can use it.
and most brass contains some zinc
it doesnt have to get to full melting though, and if there is enough zinc it has the potential to give off fumes. and zinc will burn out of brass pretty easily when its heated (granted it wont happen on a hookah but if you put a coal right on the brass and blew air on it you might be able to