Left to right: verdigris, dirty, and cleaned pennies.
Penny dipped halfway in vinegar/salt solution, clean nail, nail and screw with copper plating. See Chemistry Fun With Pennies I can see a magic show somewhere in our future where the boys turn silver into gold right before our very eyes.
More metal related stuff we've been up to: A penny covered bowling ball for the garden is in progress, too. We should have used clear Liquid Nails instead of the regular kind so we might end up grouting this when it's all covered. You can only do a little at a time and let it set up before turning the ball. There are a few examples of these online but I got the idea from a friend who in turn got the idea from someone else. You can either let it develop a patina on it's own, spray it with a number of different solutions for instant verdigris, or spray it with clear exterior grade polyurethane if you want it to stay shiny. I almost couldn't do this one because it felt kind of wrong and extravagant to use money directly as part of a craft project instead of putting it in a piggy bank. Compared to the cost of buying supplies for so many other crafts, using the pennies themselves is probably cheaper than say, buying old plates or tiles with the pennies to break and mosaic the ball.
We didn't try this experiment with pennies at the Popular Science site, thinking the muriatic acid would be a bit sketchy to use with 4 and 7 year olds, although I'm pretty sure there's a container of it on hand somewhere in the wood shop. Interesting reading though, showing what pennies are made of since 1982.
