hey the bset bet is to eat the toblerone ! Yes there was a thread on this many many moons ago, aswell as using a lens made out of ice.
Polishing a coke can with chocolate is a complete waste or time. For any survival situation you would be far better off eating the chocolate.
I spent days and I mean days polishing the bottom of a coke can, and still only got a mild dull shine. Then someone suggested I was using the wrong type of chocolate, waste nice dark chocolate instead - no better ! Crushed up mints - give it a miss. The best suggestion was toothpaste IMO, but I'd got bored of the idea by then and moved on.
Feel free if you need an excuse to waste good chocolate.
Cheers
Rich