Let's begin with a cleaning tip: If you have some tarnished or corroded brass that you want to clean, an old brass candlestick for example, you can use Coca-Cola, or any other cola soft drink, and that brass will come clean.
How Does This Work?
Cola cleans brass because it's mildly acidic.
Here's what happens: When brass or another metal alloy becomes tarnished, this means that there has been a chemical reaction between the oxygen in the air and one of the metals in the alloy.
Oxygen atoms combine with metal atoms to form what's called an oxide, and this oxide is what makes the metal appear tarnished. Acids, like the weak acid present in your can of Coke, can react with oxides to effectively reverse the process of tarnishing. The acid dissolves the metal oxides that make the tarnish, leaving only shiny metal behind.
Try It At Home!
You can try this at home, even if you don't have a brass candlestick. Leave a tarnished old penny in a glass of cola overnight. In the morning it will be shiny and fresh.
Your Stomach And Acid
If the acid in cola is so good at attacking tarnished metal, what might it do to your insides? Actually, your stomach already contains its own supply of acid which it uses to digest food.
This stomach acid is a great deal stronger than the acid in a can of Coke. Indeed, stomach acid would be an even better tarnish remover than cola!