Penny Shell?

PopSci Says:

Make a Penny Shell
Cost: $5.01
Time: 1 Hour
Safe | | | | | Dangerous

1. File around the edge of a post-1982 penny until you see white zinc.
2. Don protective gear, and drop the penny into a small bowl of undiluted hardware-store muriatic acid.
3. Wait 15 to 60 minutes until the bubbles stop.
4. With the faucet running, pour the acid into the sink through a strainer to catch the penny. (Never pour water into acid—it can boil instantly and splatter acid in your face. Always pour the acid into water.)
5. Run water through the strainer for several minutes to rinse the penny half-shells and flush out the acid.