cleaning pennies

Banana has a science experiment due this week. A science experiment. In kindergarten. Anyway, we picked up a book of easy experiments for kids early in the week and started perusing them. (The volcano had already been done.) There were several that Banana thought looked really fun--and each of them involved far more preparation than we had time for. Finally, we settled on turning pennies green. So tonight, we followed the instructions: small plate, paper towel folded in quarters, just enough vinegar to cover the paper towel, pennies, wait one hour. We followed the instructions well, and an hour later, there was still no green coating on the pennies. I began to suspect that the vinegar was somehow compromised--particularly since the early limestone tests on shells and chalk were not as lively as expected.

On a whim, I grabbed a bowl and a penny. I poured Frank's Hot Sauce over the penny and waited a minute. The penny was clean as it always had been when we performed the same trick in high school with Taco Bell hot sauce. We had our experiment. Done, right? Well, I continued to do a bit of research so she could explain--sort of--what had happened. And I came across a variation: soy sauce.

So I pulled out another tarnished penny, another small bowl, and the soy sauce. It only took about ten seconds, maybe 15, for the soy sauce to wipe the penny clean. As it turns out, a salt-vinegar solution is what takes the oxidization off best.

Imagine that. Soy sauce. Pennies. That's life.