"healing = evolution. "
Look up your definitions , for evolution to occur you need death .

As for the other stuff inhailing smoke of any kinda will in a way 'scrub your lungs' but if you didnt smoke in the first place they wouldnt need 'scrubing'.

When you say 'scrub' you are talking about your body attempting to get rid of all the tars, dead cells and other such matirial that are in your lungs as a result of smoking.

A simple explenation on how lungs work:
You breath in, oxygen and nitrogen go into your lungs and oxygen is absorbed into little air sacks and then diffuses into your blood, your blood goes around your body and picks up carbon dioxide and gives off oxygen. Blood goes back to lungs and carbon dioxide diffuses from your blood into your lungs and is expeled.
Any change to this is going to harm your lungs! Even if the air you breath in has more then 20% oxygen in it it will harm your lungs (very very slightly, almost unnotasable) so what do you think tars and other carsonagenics will do. Sure THC may be slightly benifitial but over all it wouldnt make much differance.
MullManiac Reviewed by MullManiac on . Pot not a major cancer risk NEW YORK (Reuters Health) - Although both marijuana and tobacco smoke are packed with cancer-causing chemicals, other qualities of marijuana seem to keep it from promoting lung cancer, according to a new report. The difference rests in the often opposing actions of the nicotine in tobacco and the active ingredient, THC, in marijuana, says Dr. Robert Melamede of the University of Colorado in Colorado Springs. He reviewed the scientific evidence supporting this contention in a recent Rating: 5