The cleaning of coins and tokens must be done very carefully. After all, too big interventions will spoil more than the make up for it. They can not only lead to damage, but it will also lead to the ultimate destruction of the coins.
It is not aesthetically pleased to clean the coins thoroughly. For example, copper coins are often covered with mineral layers, which are referred by the term patina. When this patina has a nice, uniform appearance, it should certainly be left untouched. The color of this patina, depends on the chemical composition, and can be very different. There are many shades, varying from black and brown to gray, blue and green. In general, these patinas is the art objects and are regarded as embellishment and therefore can also be applied artificially on modern tokens.
Coins and tokens are made of various metals. It is therefore necessary to clean them in different ways. Depending on the type of metal, the cleaning methods are divided into many categories. Before starting to clean, read the general rules. They must be strictly observed.General rules
1. Distilled Water: Always use distilled water and no tap water when making cleaning agents during the entire cleaning process. This is necessary because no constituents which are harmful to the metals are present in distilled water. This is found in rain and tap water. Distilled water cannot be replaced by boiled water.
2. Cleaning: Never use silver or copper polish and never polish the coins with a cloth. Do not use hard objects when handling the coins. While brushing the coins you often get an unnatural shine and the use of hard objects creates scratches. It is recommended to use a brush instead of a cloth during cleaning the work; for example, a trimmed toothbrush or a nail brush.
3. Rinse: The coins must be well rinsed after each treatment. This is very important. If the substances used in the cleaning process are like citric acid or sodium bisulfate (NaSO4) and cannot be removed properly from the metal, this can lead to far damage to the coins. When the acid residues they are left on the coins and come into contact with the oxygen from the outside air, a strongly accelerated formation of oxides takes place under the influence of the humidity.
Place the coins in a bath with distilled water. They may not lie on top of each other and must be turned over regularly.
If this method is not followed, discoloration may occur on the coins. A single change of water is necessary, otherwise the water will acidify and the chemicals will continue to act on the coins. The treatment is completed after approx. 30 minutes. Rinsing is sufficient for gold and silver objects. For copper other base metals, flushing alone is often not sufficient. The chemicals work through these metals deep into the coins and cannot be removed with rinsing alone. The treated coins can therefore be better neutralized.
4. Neutralize: Neutralization is, just like rinsing, a method to stop the radical effect of chemicals. The advantage of neutralization is that it directly eliminates the effect of a particular substance. A used acid is neutralized by means of a lye and a lye by means of an acid. Immerse the acid-treated coin in a bath with, for example, sodium hydroxide solution. Then rinse again well, because the coin may become basic depending on the strength of the lye and the duration of the immersion. The lye residue is also removed by means of rinsing. For the neutralization of acids (such as, citric acid, phosphoric acid), sodium hydroxide solution and household soda can be used. This is significantly a weaker lye and can therefore be used if the coins are cleaned with a weak acid solution. For the neutralization of alkalis (such as sodium hydroxide solution) citric acid and sodium bisulfate can be used.
5. Drying: The drying of the coins must be done thoroughly. As already noted, oxide formation takes place partly under the influence of the moisture. When the coins are not properly dried, all kinds of pollutants that occur in the atmosphere have a greater effect on the surface, as a result of which they oxidize much faster. Drying can be done by placing the coins on a perforated plate on the heating radiator, after they have first “hand-dried” with a soft cloth. A frame covered with nylon fly screens is also good to use. The use of a hair dryer is more effective. This allows the coins to be dried well and quickly.
6. Safety: It is necessary to exercise caution when using various chemicals. When making the solutions, make sure that the acids are put in the water and not the other way around (splashes!). Personal safety is essential: a good dust mask (mouth mask), gloves, safety goggles or face shield and a clean work jacket is necessary for safety. They are very unhealthy for the airways and the lungs. It is advisable to carry out the work as much as possible in a well-ventilated room.
7. Environmental Requirements: Chemicals is not only harmful to the environment but also to those who use them: when cleaning coins and tokens you cannot exist without acids and bases, but safe acids and bases do not exist! With regard to environmental requirements, it should be noted that all finished substances – subject to the contents – must be submitted separately to the (chemo-cart of) municipal cleaning.
You can even make use of Rock Tumbler Kits to clean the coins and here are our Top 3 picks and review about the products.NATIONAL GEOGRAPHIC Professional Rock Tumbler
Specifications and It’s Features:
The Professional Rock Tumbler consists comes along with a set of Pro Series Tumbler that is 1 lb. It also has rough gemstones, 4 grits that are already polished, in addition it also has jewelry fastenings and along with it comes an information and instruction guide set that gives you the complete idea of what to do with the Geographic Professional Rock Tumbler. The tumbler on single hand has 2 lb and it has zero leakage proof barrel that is made up of rubber. It actually has 1-year warranty. The tumbler is designed in such a way that it has some noise reduction techniques and the cover of the barrel is made up of stainless steel.
Pros Of National Geographic Professional Rock Tumbler:
The professional Rock Tumbler contains 1 lb unpolished rocks in it.
The best feature it has is the automatic shutoff time.
It also has a pucca educational guide set in which all the instructions are provided in detail.
It has good amount of durability and it is long lasting.
The fastening of jewelry is an added benefit and an extra bonus.
The noise level is also very low and not so high.
There is no leakage too.
Cons Of National Geographic Professional Rock Tumbler:
There are not major Cons but the product may face some malfunctions if the tumbler is not used properly. So it is in our hands to keep the Rock tumbler have a long life.
Our Final Verdict:
The natural geographic professional Rock Tumbler has a barrel that is filled with stainless steel cover, so automatically the noise is reduced but at the same time the operation of the tumbler is also increased and thereby reducing leakage.