How to clean ancient coins

How to clean ancient coins?

Should I clean my coins?

One of the questions I get asked most often is "How should I clean my coin collection?" Actually, the answer I give is very simple and always the same: you should not clean your coins. That is a rule that applies in the vast majority of cases. Why? Because the most likely result of cleaning will be that you will damage your collection.

Believe it or not, one of the most common mistakes made by beginners is the improper cleaning of their coins. Many times they irreparably damage them and cause them to lose their value, especially if they use abrasive commercial products, which, due to their acid composition, remove part of the metal from the surface. The result will be a coin with an artificial brightness that will alert any potential buyer.

The same can happen if you try to clean a coin using a brush. No matter how soft the bristles of the brush, it is very likely that they will end up scratching the surface of the coin and causing it to lose value.

Collectors strive to acquire coins that are as natural and damage free as possible and they will have no interest whatsoever in a coin that has been improperly cleaned

The formation of a patina depends on the metallic composition of the coin and is the result of a natural chemical process that takes a long time. The patina is a thin film that forms on the surface coins made of copper or other alloys due to oxidation. In the case of silver coins a similar process is usually called “toning”. Patina and intonation reflect the age of a coin and add aesthetic and economic value to it. If we clean a coin, it is most likely that we will eliminate or damage its patina or intonation, erasing in this way a good part of its history and beauty.

The only exception to the rule

One of the rare cases in which a coin should be cleaned is if it has become dirty with dust, grease left by fingers, or some other type of dirt due to improper handling or storage. In that case, it is always best to use distilled water (because running water contains chlorine that can damage the coin) and, if necessary, a bit of a mild neutral soap. The operation must be done with extreme care to avoid scratching the surface of the coin. For drying, it is best to let it dry alone or use a hot air to speed up the process.

The decussis, the largest Roman coin ever issued

Decussis - AE 1075 gr. c. 215 b.C. obv: Head of Rome to the right with helmet. Value mark X. rev: Roman galley to the left. Mark of value X.

The Second Punic War and the crisis of the archaic Roman monetary system

The Second Punic War (218-201 BC) was a crucial event in Roman history. An all-or-nothing struggle for hegemony in the western Mediterranean between the two powers of the region, Carthage and the Roman Republic.

At the beginning of the war, Hannibal's bold crossing of the Alps and the brilliant victories in the battles of Ticino, Trebia and Lake Trasimeno gave the Carthaginians an important advantage and left the Romans in a critical situation. Hannibal always seemed one step ahead of the Roman generals. For the campaigning season of 216 BC, the senate decided to gather a much larger army than the ones Hannibal had defeated, trusting that the numerical superiority would allow the Roman commanders to neutralize his tactical talent. They sent 80.000 men to face the Carthaginians in a decisive Battle.

Despite these enormous efforts, the 216 B.C. campaign ended in complete disaster. The Battle of Cannae was the greatest defeat of the Romans in all their history. In spite of his numerical inferiority, Hannibal made with his troops a brilliant pincer movement. The Roman soldiers, attacked from all sides, were annihilated in an unprecedented massacre.

The defeat left the Republic in a desperate situation. The losses could not be replenished in the short term and there was no longer enough metal to continue minting Roman coins to the standards in force before the start of the war. The quadrigatii were devalued by reducing their silver content and the bronze coins by reducing their weight.

The decussis

The years following the defeat of Cannae were critical for Rome. Devaluations seem to have led to a gradual loss of confidence in Roman currency. The Roman authorities reacted minting new types of coins. A particularly interesting issue is that of a complete set of bronze denominations that the English numismatist Michael Crawford dates to the years 215-212 BC. and includes large-sized cast coins.

The decussis is particularly striking because it is, in fact, the largest coin ever issued by the Roman state in all its long history, with 1075 grams of weight. Dea Roma is depicted on the obverse, wearing a Phrygian helmet and with the mark of value X behind. On the revers, we see the typical galley of the Roman bronze coins. These large cast coins were only a short lived experiment and are extremely rare. Only four decussis are known today, three of which are in museums and only one in the hands of a private collector, having been auctioned in 2010 for 240,000 Swiss francs.

The Brescello Hoard – the largest and most valuable hoard of Roman coins ever found

Brescello, the ancient municipium of Brixellum, is a small town in northern Italy near Modena. Originally, it was a Gallic settlement on banks of the Po River that was romanized after the area was annexed by the Roman republic. The city was transformed into a Roman colony in the period following the assassination of César and it quickly became an important transport and communication hub.

It was in this city that in the year 1714 one of the most remarkable numismatic discoveries ever recorded took place. A peasant, while ploughing a field, accidentally found a vessel containing about 80,000 republican aurei, that is, approximately 650kg of pure gold!

The treasure was composed entirely of only 32 varieties of types coined between the years 46 and 38 BC, so it is quite safe to assume that it was buried in 38 or 37 BC. The latest coin identified was an aureus minted by Octavian that mentions Agrippa as consul designate for the year 37 (Crawford 534/1).

The hoard was most likely the treasure chest of a warlord of the period of civil wars. Its nominal value was 2,000,000 denarii. To put that figure on an understandable scale, it must be considered that the annual pay of a legionary in that period amounted to 250 denarii. Of course, the current value of the treasure would be much higher. A fairly conservative estimate of about $ 1000 on average for each coin gives a total value of $ 80,000,000. Undoubtedly, it is the most valuable hoard of Roman coins ever recorded, and by a wide margin.

The sheer size of the hoard is a good indicator of the enormous quantities of gold that were coined after Caesar’s victory in the civil war against Pompey. The new Caesarian aurei were minted by the millions and an important portion of this output was accumulated by a small elite, mainly in the entourage of the great political leaders of the period.

Unfortunately, very few of the coins discovered at Brescello survived. At the beginning of the 18th century there was not a sufficiently developed numismatic market as to absorb such a number of ancient coins. Therefore, after dispersing a relatively small part, the rest was melted to mint ducats!