Posted by Thomas on August 31, 2003 at 14:16:49:
In Reply to: Ketchup? posted by Dan Schultz on August 31, 2003 at 09:42:38:
We used ketchup in my high school science class a long time ago to clean pennies. We were told from this experiment that it was the high amount of citric acid found in tomatoes that removed the tarnish, and made the pennies shiny.