Coin dealers and collectors are apprehensive in purchasing coins in their original state and normal condition of preservation. Never clean a coin if you think, know or even don’t know its value.
Under no conditions clean coins with commercial metal and jewellery polishes or silver stain remover, which will get rid of the toning that usually collects over time on copper and silver coins. Removing tarnish often leaves minute spots or scratches that can substantially diminish their numismatic worth by up to 90 percent! Almost 20 percent of coins exposed to coin dealers are discarded since they were improperly cleaned, polished, or their toning was chemically improved. Keep in mind, you cannot unclean an inappropriately cleaned coin.
Take your coins to a skilled coin cleaner to do the cleaning. Expert dealers often propose a coin cleaning service using a method called “dripping” that ought not to be attempted by an amateur. At all times hold your coins by the edges to avoid fingerprints on the surfaces.
If your coins are so tarnished that the date and particulars cannot be determined, consult a trained expert for guidance before attempting to clean the coins to avoid damage.
If you have to clean your newfound coins, you should clean them with the slightest damaging means that will give the essential outcome. Take note that exceptionally dirty or marked coins, if not cleaned inside a sensible length of time, can eventually corrode and become spoilt past repair. Following selecting the means you will use, you should test on low-value coins previous to cleaning high-value coins. Do not be tempted to use harsh chemicals, sulphuric acid, polishing cloths, metal brushes, rock tumblers, which can cause damage to your coin.
If you know a coin you are selling has been cleaned, you must make known that detail to the buyer.