Why the dismissive & disparaging tone to your reply ironraven? Weren't we all taught as children that, there are no such things as stupid questions? And just to clarify things, I do know that these tanks are hazardous, that’s why I asked about proper disposal. Also I don't smoke but if I did, I wouldn't do a fool thing like smoke around them. And lastly you asked where the rust is, it's on the threads. But don't bother with any replies; I got all the information that I was seeking from the other far more constructive posts on this thread..