Cleaning Pennies With Soda

Who hasn't enjoyed a nice cold Coke or Pepsi on a hot summer day. I mean nothing is better after a day in the sun then throwing back an ice-cold soda. As refreshing as it is to the human thirst, I wonder if it could refresh old pennies.
With this in mind I decided to give it a try. I basically grabbed some old pennies dated from the 1960's-to ensure they were dirty enough and dropped them into a glass full of Coke.
I let the soda work for about 7 days cleaning the pennies. However, I have to admit that I was somewhat disappointed. My quest to clean pennies with good old-fashioned soda was a failure.
The soda did remove some of the crud that had been deposited on the pennies over the past 40 years but came nowhere close to actually cleaning the pennies.