I've posted about this before, but here's why you don't smoke anything using tin foil or tin cans:
Symptoms/Diseases related to aluminum toxicity: Rheumatoid Arthritis, Autoimmune Disorders, Alzheimer's, allergies, constipation, memory problems, epilepsy, and heart problems, hyper- activity, kidney diseases, Osteoporosis, Parkinson's, Schizophrenia, ulcers and more.
In an interview, Michael J. Fox was asked why he thinks he got Parkinson's disease, and he answered "Too many tinners as a kid" Tinners meaning a pop can.
You can read up about it below. or just go to google and find your own sites. the first one's good...
http://www.relfe.com/IDetoxamin/aluminum_toxicity.htm
http://www.lef.org/protocols/prtcl-088.shtml#metals
http://www.magneticclay.com/productlist.shtml-katie