I think this is a relatively new tradition. I certainly didn't grow up on it, but we've been making leprechaun catchers since the kids were in pre-school, and it's darn fun. It's super fun for me now because I put out some shoe boxes and sparkly shamrocks from the dollar store, and they took it from there.

Once they got done with the engineering (how can you get the leprechaun to come into your trap and have the lid close?) and the artistic--shamrocks, rainbows, pots of gold, all to lure the leprechaun in--we moved on to the science experiment.

Of course, shiny pennies make a great lure, but our pennies are dull. We tried three different methods of shining: erasers, toothbrush in ketchup, and the vinegar/salt dip. Then we tried combos. All agreed that the dip was great, but ketchup with a little extra vinegar was successful too. It's such a fun experiment because the results are so immediate and startling. Suddenly, you have gold. I had read somewhere that you had to use pre 1980 pennies because they changed the copper content after that, and the results would not be as good. But we also tested pre and post pennies are were happy with both. Maybe are standards aren't as high.

The kids were at it for three hours with only one incident of ketchup in the eye.