If you want to go ahead and clean corrosion off of your old coins, baking soda likely is the safest route to follow. Wet the affected coin with clean tap or distilled water, roll in baking soda, then gently scrub with a soft toothbrush.
Before cleaning old coins, consider that appraisers and coin experts suggest not cleaning collectible coins yourself because the coins may lose their value. Using chemical cleaners or scrubbing the coins can leave behind scratches and marks, easily seen by a skilled coin appraiser.
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.
This is never advised for the general public. There is no benefit to attempting to clean a collectible coin. Copper never re-tones to its original color and look anyway. Put down the polish before you destroy something historical and throw away a fortune.
The vinegar and salt mixture dissolves the outer layer of dirt. Flip the pennies over and wait another 30 seconds. Then remove them, rinse them with water, and dry. Now you have two clean, shiny pennies!
The cleaning of the coin is made by friction of the piece in a cotton flannel with a small amount (a pinch) of calcium carbonate – a neutral product, with a very thin granulation not to scratch the piece (approximately the same granulation as toilet talcum). Calcium carbonate may be used in any metal.
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.
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.
Brasso is a metal cleaner that some people will already have on hand for other home applications and it is definitely the quickest and easiest method to clean pennies.
Coke and off-brand colas will quickly remove the tarnish. Just don't drink the coke afterward. Coke contains phosphoric acid that cleans the oxides. Try a variety of citrus juices to see which works best or simply let your pennies soak in lemon juice.
Denture Cleaning Tablets
Soak the pennies in a container with denture cleaner. From time to time, shake the container. It's best to let the pennies soak overnight before rinsing and drying them.
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.
Collectible or valuable coins should not be cleaned as cleaning almost always reduces their value and rarely improves their grading. Though it may seem that a bright, shiny coin would be more appealing to coin collectors, the truth is most prefer coins to possess their natural color.
Hard Plastic Holders are preferable for more valuable coins. They are self sealing, and not known to contain any materials that harm coins and offer good protection against scratches, touching and handling, air and chemicals, and other physical damage.
SILVO® can be used to restore jewelry, coins, chrome bathroom fixtures, and many more items. Keep your precious metals bright and shiny with regular cleaning using SILVO®!
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.
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.
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.
The oil-base makes WD-40 reasonably effective at removing it without a lot of work. There is of course some sacrifice when this stuff is removed but fortunately the metal underneath is in pretty good condition and the coin, in hand, is much more presentable.