To avoid causing wear, collectible coins must be handled with great care. The grade of a collectible coin is dependent on the coin's condition. The grade of a coin dictates its value and price. The higher a coin's grade, the more it is worth. For this reason it is critical that handling of coins be absolutely minimized! Each handling risks the coin being exposed to substances that can cause flaws such as spotting and color changes that reduce the grade and value of the coin. You can obtain special holders that are designed to protect your coins from basic handling. Only take a coin out of its holder if it is absolutely necessary to do so.
An uncirculated or proof coin should only be touched along its edge. Even simple fingerprints can decrease the grade and value of a coin. It is a good idea to develop the natural habit of picking up coins by their edges to avoid fingerprints on the surfaces.
Additionally, a coin collector should not hold any coin in front of his mouth. Even the smallest drops of moisture can lead to spots on the coin over time. If you have to put a coin somewhere other than in its holder, always make sure that you put it on a clean and soft surface. A pad made of velvet is the ideal material to protect a valuable coin. You could also arrange your coins on a clean, soft cloth; however a clean sheet of blank paper should be okay for coins with less value. Most vitally, never drag coins across anything. Scratches and wear can occur if you do this. It may be wise to wear comfortable, clean white cloth or surgical gloves and a mask when handling valuable coins or quantities of uncirculated and/or higher grade circulated coins.
Experts in the coin industry advise people to never clean their coins. Even if you believe the coins will be prettier if you clean and shine them, resist the temptation as collectors prefer coins in their natural state. If you clean a coin it could actually lower its value by over fifty percent. Small scratches can even be caused by wiping the coin with a soft cloth. When a professional grades a coin which is collectible, they look at it under magnification. This magnification allows the small scratches and flaws to be seen, thereby making the coin less valuable.
Trying to restore a piece of art is what you might compare cleaning coins to. It is wisest to leave that job to someone specially trained to do it. These individuals are trained to know what supplies and methods are most effective for cleaning without causing harm. Soaking your coins in olive oil or soapy water for a few days sometimes will remove dirt or other substances from them. Afterward, the coin should be thoroughly rinsed with regular tap water. You can dry off the coin with compressed air, or allow it to air dry. It is vital that you never rub a coin, not even to dry it.
Sometimes coins are affected by toning, which occurs naturally. This chemical reaction causes the coin to become tarnished due to atoms on the coin's surface reacting with sulfur compounds. This can unfortunately not be undone. Professionals may use a dipping procedure which will clean away the top layer of molecules on the coin; although, a coin which has developed a natural patina may have increased value.