lm, the galvanized coating on a trash can,when heated, can produce toxic chemical that will be deposited on the meat that will make you quite sick.
That said, there is lots of info on the internet about making an electric smoker out of a garbage can and an electric hot plate. Apparently this arrangement doesn't produce adequate heat to release the toxins.
Find a new or food grade 30 or 55 gal type barrel to experiment with instead. Probably not as cheap, or easy to find, but much better safe than sorry where health is concerned.