Sadly, it is illegal in Canada to deface currency in either note or coin form.

Quote from TheActionKid:
This penny business is brilliant, I am now looking into ways of putting it in action! As soon as I heard about this a *light bulb* went on! The only problem seems to be the legality issues as mentioned before, but I am a pretty resourceful individual and can find loopholes and ways around certain things.
-TheActionKid

Quote from Rearden Metal:
With copper now at $3.72/pound, every single pre-1982 U.S. penny now contains 2.41 cents worth of copper ore.
It may or may not be legal, but a handful of shrewd businessmen <b>will</b> make millions of dollars by devising an efficient way to sort pre-1982 pennies from the newer coins, taking these pennies out of circulation by the tens of millions, smelting them down, and then selling the ore. There may be opportunities which are even <b>more</b> lucrative, using non-U.S. coins.
Daytrading was the path to easy money in the late 90's, while online poker filled this role from '03 to '04. <b>Today's</b> easy money is now there for the taking- by smelting pennies.
I know nothing about mechanical coin sorting or metallurgy.
Seed money? That, I <b>do</b> have.
So... how do I get mine?