Quote Originally Posted by hash in hand
incomplete combustion produces less carbon dioxide and more carbon ("black residue") and carbon monoxide. carbon monoxide is a poison because it replaces the oxygen in your blood. neither carbon or carbon monoxide are acidic and hence do not corrode the aluminium.
You're assuming that cannabis is made of nothing but pure carbon.
Which it isn't.
Take coal for example, which is made of plant material. Lots of carbon but that's not all.
The nitrates, phosphates, etc found in plant matter are still in the coal, which, when burned, releases them into the atmosphere and they are part of acid rain (nitric and phosphoric acids).

Quote Originally Posted by hash in hand
so shove that in your pipe and fuck off
You have a nice day too, now, y'hear?