The ones out playing forest fire don't need any new ideas, but they'll find them.
The kid with the balloon needs to pass chemistry just as the first step.
You won't get near out what got put in even if you used cheaper aluminum and acid. Or zinc, or iron, etc.
More coal-equivalent got used making pure metal than you can get out burning it.
You're better off burning coal and better than that using green energy, even wood.