Best Answer #39: from Doug Sears:
" Because nickel was an important mineral for the processing of stainless steel and other alloys needed for producing war materials for World War II, it put a great strain upon Canada's nickel mines. By 1942, it was decided that nickel would have to be substituted for another material. The Royal Canadian Mint experimented with different alloys, till they decided that a coin made of ‘Tombac’, which is a brass alloy, composed of 88% copper plus 12% zinc would work. The idea had come from the British 3-penny piece that was first issued in 1937. Nickel used for coins was suspended late in [1942]. This alloy, tombac, quickly tarnished to a brown hue, so the new coins were made with 12 sides to avoid being confused with the penny coins. The coin had King George VI on one side, and the flip side had the beaver. Late in 1942 about 3,400,000 were struck. In 1943, a new design was introduced to bolster the war efforts. The torch and ‘V’ on the ‘tail side’, symbolized sacrifice and victory (the V also indicated the denomination, the idea coming from the US Liberty 5-cents pieces of 1883-1912). Around the inside of the rim of the coin, a Morse code (dot-dash) pattern reading, ‘We Win When We Work Willingly’, was used.

The designer was the chief engraver of the Royal Canadian Mint, Thomas Shingles (whose initials T.S., are at the right of the torch on the coin). He cut the master matrix entirely by hand- a feat few present-day engravers can accomplish. Production of this issue; also in tombac, reached 24,760,000.

This alloy, tombac, however, was replaced with chromium-plated steel in 1944-45, because copper and zinc were also needed for the war effort. These coins, because of the manufacturing process, were unfortunately vulnerable to rusting at the edges.

Historical notes on Canadian Coinage:
- Canadian cents are actually older than Canada! The first bronze cents were struck on 1858 for the Province of Canada. - First coin club - Montreal,1862. - The Royal Canadian Mint was opened on January 2, 1908, in Ottawa. - The Canadian Numismatic Association, was founded in 1950, (which is celebrating its 50th anniversary, August 2nd-6th, 2000). - The Canadian Numismatic Research Society, founded in 1963. "

Sources:
- Warman's, Coins and Currency 2nd Edition;
- The Charlton standard catalogue of Canadian Coins, 53rd edition;
- Haxby, J.A., Willey R.C., Coins of Canada, 17th Edition, 1999