At the risk of sounding like a douche;

All my life I have been told and read that smoking from copper is extremely poisonous. My father has worked with metals all his life and is in bad shape because of it so I have had these things drummed in to me. I am really surprised to hear so many people singing its praises.

Stainless steel (or just steel) or cast iron are the only metals you should be inhaling from in my opinion, "they" say brass is fine but brass still contains copper so to play it safe I don't like to use it.

Aluminium is very bad for you too even though for some reason head-shops think its acceptable to use for bong heads and downpipes. It releases aluminium oxide when heated and that stuff will hurt you badly with the first symptoms being you losing your hair if you have enough of it in your bloodstream.

Please guys, I maybe new here and don't know anyone yet but I still care about your health!