Copper prices are expected to keep climbing, which makes old copper pennies a cheap long-term bet — but only for people willing to sit on them for years.

• Pre-1982 pennies are still copper and can be pulled out of ordinary change at face value, while their metal is already worth several times that.
• Deutsche Bank has raised its copper forecast sharply, and the case is for prices to keep rising well into the next decade.
• The point is to buy while copper is unloved and cheap, not to flip the pennies next week for a quick profit.
• Unlike rare paper money, graded copper coins would carry both collector value and rising metal value.
• Anyone who can't afford to tie up small amounts of cash for years has a bigger money problem to fix first.

Outlook: Copper looks set to keep grinding higher, so the payoff on hoarded pennies is a long wait rather than a quick trade.