When the copper oxide (the pennies) and the phosphoric acid (the cola) get together in the bath, the acid reacts with the copper oxide on the pennies and dissolves it. That's why the pennies get shiny. What else could you put into the cola bath?
Who would have thought that your favorite soda is also a great cleaning agent? Yes, that refreshing can of Coke that you like to drink by the pool can also clean coins. Coke's phosphoric acid can clean the oxides that cause tarnish and corrosion.
Coke and other sodas contain various acids and some of the strongest acids available on the market. For example phosphoric acid. This acid reacts with the copper and the zinc of the coin and dissolves it.
Our cola contains phosphoric acid which is why cola is acidic. The acid reacts with the oxide rusty coating that has covered our coins and returns them back to almost as good as new.
Restore shine to coins and jewelry
If, for some reason, you care about how shiny your pocket change is, simply drop the grimy coins in a Coke bath and leave them overnight. In the morning, pour the Coke down the drain, rinse the coins in warm water and pat them dry.
Vinegar. A common ingredient in DIY eco-friendly cleaners, the acetic acid in white vinegar can help wear away the contamination on your coins. Soak your coins in a glass or other non-corrosive container for at least 30 minutes, up to overnight, and then wipe with a clean cloth or scrub gently with an old toothbrush.
Coins that are obviously dirty can be run under water (with a very mild detergent) and left to air dry. A short soak in olive oil may remove unwanted gunge. For cleaning corroded coins the damage is already done, they will forever show pitting into the coin surface. This is as far as anyone should go with cleaning.
Most Cleaning is Destructive: It Can Literally Change the Surface of a Coin. Any cleaning that requires rubbing leaves microscopic scratches. They are not apparent to the naked eye, but a collector will see them. A collector will look for them.
Most coin cleaning products are abrasive, and could damage the coin. Non-abrasive chemicals can still react with the other metals found in some old coins. The physical act of scrubbing or polishing can also wear down the design, destroying one of the most important factors in deciding a coin's grade.
Distilled water is recommended as tap water contains chlorine. The coin is dipped into olive oil which according to Hudgeons, works best for common copper or bronze coins.
While cola is good for removing tarnish on some metals, on others such as iron, tin and steel, it can corrode the metal.
The empty soda bottle
Every time you get a $2 coin, pop it in the soft drink bottle. It's thought that a 600ml soft drink bottle can hold somewhere around $880 worth of $2 coins. Alternatively, little tykes can start with a 250ml bottle which will hold around $350 worth of $2 coins.
Moisture can discolor coins, and saliva can create spots on coins that are difficult to clean. Store properly. Use acid-free and PVC-free holders to store your collectible coins. Both acid and PVC can damage a coin, and PVC can create a sticky, slimy green coating on a coin's surface.
What happens when you mix the two drinks? Pouring milk in Coke or vice versa results into a reaction of phosphoric acid in the Coke to milk's proteins causing them to stick together, creating dense lumps that later settle at the bottom. In short, the milk curdles up.
How Does It Occur. Toning occurs naturally over time. It is primarily the result of oxygen and/or sulfur reacting with the coin's metal. However, the toning process can be accelerated by heat, moisture, and various chemicals in the environment.
Gold Standard Water Filtration
That's because McDonald's filtration system is top tier. McDonald's filters its water before they add it to the soda fountain, so it guarantees your Coke will always taste fresh—even if the water that they start with isn't great quality.
Contaminated Coin Procedures
The Federal Reserve does not accept deposits of Contaminated Coin. Customers who wish to deposit coin after decontamination should contact their FedCash Services contact.
Judge the age and consistency of the color, its depth and evenness. The underlying luster should be undisturbed and in a perfect cartwheel pattern, this being especially visible about the obverse stars. Look for hairlines or other imperfections that may indicate the coin was cleaned at some time in its past.
Make sure your coins have been cleared of all dirt, debris and other objects prior to visiting the kiosk to ensure a successful transaction. Items like food, screws, dirty or sticky coins and other objects will jam the machine.
Don't clean your coins! Not only does this cut their value by as much as half (or possibly even more), but it will be an immediate deal-breaker for many dealers who would've otherwise wanted to buy your coins if only they were left in their original condition.
This is because anything that touches a coin has the potential to damage it at the microscopic level. The more abrasive a cleaner is used to clean the coin, the more likely it is to remove the upper surface of the coin - damage that can never be undone.
However coins will often have on them built up dirt and grease. This may get into the nooks and crannies of the coin. To remove this type of build up you can use a weak detergent solution with a soft cloth (Clux Wipe or similar will do the trick) to take this material off.
Rub the coins with a soapy water solution.
If you don't see any dirt or grime coming off of your coin, let it soak for about 5 minutes before trying to scrub it again. Soapy water is a great solution for removing surface dirt without damaging or scratching your coins.