That's what I thought.
Hi Johannes
I just happen to have a penny, a bastard file and a propane torch handy.
Guess what? Pennys are copper plated zinc.
I found some scrap copper wire and sure enough it gives off a green hue just like the message text in this reply.
I expected to find the use of CU in making fireworks but its probably more expensive than Barium.
On a side note, the US penny cost .81 ¢ to manufacture. Maybe we should mint more pennys to bring the national debt down ;)