You should've always stack them.

Interesting facts feom Wikipedia...

**When copper reached a record high in February 2011, the melt value of a 95% copper cent was more than three times its face value. As of January 21, 2014, a pre-1982 cent contained 2.203 cents' worth of copper and zinc, making it an attractive target for melting by people wanting to sell the metals for profit. In comparison, post-1982 copper-plated zinc cents have a metallurgical value of only 0.552 cent. Prior to 1982, the fluctuating price of copper periodically caused penny shortages, as people hoarded them for their perceived metallic value.**

**Most modern vending machines do not accept pennies, further diminishing their utility. In addition, the production cost has long exceeded the face value of the coin, reaching 3.69 cents in 2024.**

**In anticipation of people melting down U.S. pennies and U.S. nickels for profit, the U.S. Mint implemented new regulations in 2006 that criminalize the melting of pennies and nickels and place limits on export of the coins. Violators can be punished with a fine of up to $10,000 USD, imprisoned for a maximum of five years, or both.**

Oh, these are the copper made ! You gonna be rich 🤣