How to maintain ancient coins?

First, the maintenance of ancient currency.

There are two major problems in the maintenance of ancient coins: storage and rust removal. Here, we will focus on the storage methods:

At present, a transparent plastic bag is commonly used to store ancient coins, which are divided into three specifications: 6*4, 5*3 and 4*2, and can store all kinds of coins. It should be said that it does have many advantages, such as convenient access, small size, convenient carrying and convenient viewing, but it is only suitable for short-term storage. Because this kind of plastic bag is made of PVC, some inferior ones are simply recycled plastic, which has poor air permeability. It is easy for moisture to enter in rainy days and it is difficult to discharge it, which leads to moisture in the bag and corrosion of ancient coins. I have a deep understanding of this. Once harmful rust such as powder rust breeds, the whole money body will become a glistening piece, which is very ugly and greatly reduces the appearance of ancient money. In addition, the import of this plastic bag is small, which is easy to cause direct damage to some fragile coins. Therefore, if you plan to keep your coin for a long time, you'd better not use it.

Some people also use foam plastic to add pins or threads to cardboard to save ancient money, but it has many shortcomings such as large storage volume, high cost and inconvenient carrying and storage. Moreover, the needle is made of iron, which is in contact with copper coins for a long time, and is prone to displacement reaction, rust water and pollution of ancient coins, so this method is rarely used at present. Not long ago, Nanquan Folk Collection Store developed a plastic storage box. The box is 20cm long,1.2cm wide and1.5cm high. The boxes are made of polymer polypropylene, and each box contains 15 coins with a diameter less than 3CM. The product is made of special materials, which will not cause any harm to coins, and has a beautiful appearance and can be stacked. It is an ideal coin storage device seen so far.

Knives and cloth coins are often bulky and need to be stored separately, but there is no special storage device at present. A few collectors with deep pockets often ask people to make special storage devices, but the opening cost of a mold is more than 1000 yuan, which is obviously too expensive for small and medium-sized collectors. Ordinary people can choose some discarded paper boxes, such as a longer paper box for putting ginseng, and it is best to add some absorbent cotton and sponge under it to reduce friction. If you distribute coins, you can choose some checked cartons.

More precious coins are usually stored in round plastic boxes. There are many models of this plastic round box, so it's best to choose the model that matches the size of ancient money. For thin, crisp and tender ancient coins, cotton wool, paper and other things were put as cushions. A rare treasure was once packed in boxes such as mahogany and ivory to set off its preciousness. Of course, if we are unconditional now, we don't have to follow suit. In order to strengthen the protection measures, special measures such as vacuum packaging and nitrogen filling can be adopted to slow down the oxidation rate.

Iron money needs more attention because it is easy to oxidize and corrode. Some people think that iron money can rest easy after rust removal. In fact, many iron coins will quickly generate new rust even after rust removal, just like rice crust. In the long run, Qian Wen will become shallow and vague, and even be destroyed. Therefore, it is best to store iron money in a dry paper box or hard plastic box, and put as much desiccant as possible around it. If you can, you can go to the hardware store to buy some "metallographic anti-rust paper", cut it into small pieces, and package each dollar separately to play a sealing role; For expensive iron coins, it is best to fill in the blanks. On average, every three to five months, you can pick a dry and sunny day, take out iron coins one by one to ventilate and turn over.

Some ancient coins will be severely oxidized due to their own copper problems or long-term exposure to humid and acidic environment. Numerology calls this phenomenon "invisible body". Due to the serious oxidation, "bodiless" money is crisp and tender, like a piece of tofu. Therefore, the "unborn" money is generally not handled, so it must be handled carefully, and it must not be thrown away at will, otherwise the money will be destroyed. Some knives and cloth coins in the pre-Qin period are relatively old, and the phenomenon of "being born out" is more common. A Qian Shang once collected a batch of Ming Dao of Yan State. It goes without saying that about two-fifths of the knives are broken due to the widespread phenomenon of "being born out of the body" and careless storage. Therefore, we must pay attention to the preservation of "intangible" money.

What is worth mentioning is the problem of coin rubbings. Coin rubbings are one of the most important ways to preserve coin images, which can be said to be essential. But the rubbings of coins will do some harm to the coins themselves. Whether it is brown brush, expansion bag or water, it will have different degrees of influence on coins. Some people say that "rubbings hurt money". The word "injury" reflects the harm of too many rubbings to coins, which may have serious consequences such as breakage and fracture. Therefore, it is not necessary for us not to rubbings, especially some light, fragile, bodiless and lead-made ancient coins, let alone rubbings easily.

Rust removal technology

Before removing the rust of ancient coins, we must first recognize whether the rust removed is harmful to ancient coins. Many friends like "one pot end" when removing rust. They think that only in this way can they be as clean as new and moist as jade, and as a result, the coins are unrecognizable, lifeless and very undesirable. Generally speaking, the rust color on ancient coins should be preserved as much as possible. Proper rust can not only enhance the ornamental value of ancient coins, but also give people a kind of "green jade" aesthetic feeling, which is an important basis for distinguishing authenticity. At the same time, I'm afraid you don't know that rust color is also an important basis for pricing coins in foreign auctions. However, the rust that affects the texture or appreciation of the coin itself must be removed. Here are some ways to introduce yourself:

(1) vinegar bubble method. Wash the ancient coins, put them in a small dish, and pour a little vinegar until the coins are submerged. Take it out after 24 hours, brush off the residual rust with a small brush until the money lines are clear, then wash the vinegar with clear water and wipe it in the shade. This is a simple and common method, which can deal with all kinds of floating rust, but the effect is often not ideal. Many ancient coins will have yellow marks on their surfaces after soaking in vinegar, which will affect their appearance.

(2) Boiling water immersion method. Sometimes ancient money is covered with a layer of floating soil, but it can't be washed clean. In fact, this so-called floating soil is actually a kind of soil rust (a mixture of soil rust and copper rust, which is an alkaline hard floating object). For this kind of corrosion, we can first put the ancient coins into the bowl, and pour the boiling water with the temperature of 80-90 into the bowl until the coins are submerged (not too fast). After 5 minutes, take out the money, brush the pattern and body of the money with a small brush, and dry it in the shade. When encountering ancient coins with serious soil rust, hot water can also be heated to boiling to make the soil rust fall off. Practice has proved that this method is very effective in removing soil rust and has the great advantage of not destroying the patina of coins. Ancient lead coins, such as blurred money lines or rusty lumps, can also be separated by this method.

(3) Dry brush method. When the copper rust or rust is shallow, chemical means such as vinegar bubble should be avoided as far as possible, and dry brush can be used to clean the lines. The specific method is: choose a large oil painting pen, and cut the brown hair on the pen head to a position only 0.5-0.7cm away from the root (to ensure the root is uniform) to use. First put the ancient money to be brushed on the glass plate and fix it. If it is uneven, you can put some cloth under it, hold the root of the oil painting pen and brush evenly. Pay attention, or the effect will be poor. After the floating rust is brushed off, it can be washed with clear water.

(4) heating method. This method is mainly used to corrode shallow iron coins. The molecular structure of ferrous oxide (FeO), the main component of rust, is relatively loose, and its adsorption with iron and Qian Qian is far less than that of copper coins. Therefore, some iron coins can be separated from corrosion by using the principle of thermal expansion and cold contraction. However, when using this method, we must pay attention to the following points: a Don't directly heat the derusting iron money on the fire. When heating, add containers (such as metal containers such as pots and cups), because iron coins will produce abnormal phenomena such as discoloration, deformation and even fracture after direct combustion, so it is best to add some water. The heating time should not be too long. Generally, after heating for three or four minutes, take it out and cover it with a cold wet towel, and the rust will naturally fall off. C the object of rust removal by heating method should be iron money with good iron property and rust on the surface. Never use heating to remove rust from severely rusted and very fragile iron coins, otherwise the already fragile coins will be broken and shattered due to high temperature.

(5) Scraper method. Some hard green rust plates form blocks, covering the whole money body. This rust looks hard, but it is not firmly attached to money. In this case, we can use a knife scraping method. The tool is simple: a carving knife (preferably a straight knife), aim at the bottom of the rust block and carefully shovel it off. If a large piece of rust can't be dug out at the moment, you can put the money on the glass plate first. If the money is uneven, put some pieces of cloth on the lower end, put the knife vertically on the rust block, and hit it with a heavy object (such as a hammer) several times, and the hardened rust block will collapse. However, when using this method, we must pay attention to it properly. If we are not careful, we will scrape the money black and blue, or the whole money will be damaged. Therefore, if you are uncertain or use this method carefully, it is better.

When all the above methods are ineffective, or when we encounter particularly hard red, green and hard rust and have to remove it, we can only use chemical means. Because the common component of this rust is mainly alkali or copper carbonate, it should be neutralized with weakly acidic acetic acid (which is sold in general chemical reagent stores). The specific steps are as follows: firstly, wash the ancient coins and soak them in acetic acid solution for one hour (the concentration of acetic acid solution is about 50%); Then pick it up and spread the rust of the stripped money; Finally, gently brush the money body with a brush until the text pattern is clear, and wash it in the shade. Although acetic acid is weak in acidity, it still belongs to the category of medium-strong acid. Therefore, direct contact between hands and acetic acid should be avoided when derusting, and it is best to use certain tools (such as tweezers) or protective articles (such as rubber gloves). Some powdery rust is stubborn, even if vinegar is used, it is difficult to remove it, and it will soon come back and breed all over the body, so it can also be removed with acetic acid. The specific steps are the same as above. Iron money can also rust with acid. The concentration of acetic acid should not be too high, and the best content is below 0%.

Generally speaking, silver coins rarely rust, because the chemical properties of silver are relatively stable and it is not easy to oxidize and rust, but there are exceptions. In this case, we can drop dilute sulfuric acid with a concentration of 8- 10% on the corroded part, and after the rust is decomposed, rinse it with clear water and blot it with absorbent paper. But don't use strong acid. Although strong acid won't hurt the silver coin itself, it can be used for silver coins with low silver content. Using strong acid will affect the smoothness, pockmark on the surface and affect the appearance.

Second, the repair technology

We often compare some coins with small defects to "chicken ribs". It is useless to keep them and it is a pity to throw them away. If you have a few coins like this on hand, it's really a headache. In this case, you might as well do a "minor operation" on the coin yourself, turn harm into benefit, and turn waste into treasure, which may have unexpected effects!

1. Repair ancient currency

Because copper has good flexibility (mainly brass) and is not easy to break, you can first wrap the uneven ancient coins with tissue paper, then take two slightly thick wooden boards, put the ancient coins in the center of the boards and press them hard on a vise or a flat table, or you can pad a thick cloth on the coins, put them on a wooden table and gently knock them flat with a hammer. Need to be reminded that the unevenness of the coins processed in this way must be caused by the day after tomorrow. If the bulge of this money is obviously left by casting, it will definitely not work.

In the past, the small holes in ancient coins were often repaired by indigenous methods, that is, hot resin was filled in the gaps, cooled, polished and leveled with a sharp knife, and then painted with pigment to make the color of the repaired area coordinate with the surrounding area; Or simply paint it with mud and 502 glue. It should be said that the effect is not ideal. Moreover, the resin ages quickly, can not be stored for a long time, and is generally easy to be seen through. Here is a good method for your reference:

Wash the old coins to be replenished, dry them and put them on a flat plate with a piece of paper under it. Then, use a knife to slightly enlarge the wound to be repaired, so that the outer edge is at an oblique angle of about 30, and the dirt is blown away. Take other abandoned ancient money, such as ordinary money in the Tang Dynasty or the Northern Song Dynasty. The more rust, the better. Scrape off the rust block with a knife, then grind the rust into powder, gather it on paper, pour it into the gap, fill the small hole with a small stick until it is 1-2MM higher than the plane, and drop it on the rust powder with newly developed 502 glue to make the rust powder wet and shrink naturally. Two minutes later, before the 502 glue hardens, immediately flatten the hole filling place with a knife. The color of the hole after filling is almost the same as that around, and the effect is ideal. The key of this method is to use 502 glue which is particularly volatile, and it must be newly developed. Never use the sealed glue, otherwise it will seriously affect the repair quality. Broken coins are generally worthless, but it is another matter if some extremely rare and precious coins are broken. For example, there are only four Jingkang Shi Xiaoping ingots, one of which is split in half and then overlapped with solder. However, the bonding effect between broken coins and solder is not ideal and has been eliminated. At present, most of the broken coins are glued with 502.

2. Repair of silver coins

The repair of silver coins is mainly aimed at the cracks on silver coins and the incomplete seals that affect the appearance. It should be pointed out that all kinds of stamps are marks made by banks in the old days to identify the authenticity, which can reflect the circulation process of money from one side and have great research value, so those complete stamps should be preserved as much as possible. The specific repair method is: first, remove the dirt from the gap that needs to be repaired, take a small solder pen, remove a little rosin from it, insert it into the power socket, dip it in a little tin, and quickly wipe off the excess tin liquid with a napkin (if it is too late to wipe it, you can touch it again with the solder pen until the gap is filled). After the tin liquid is completely condensed, it can be polished and leveled with a sharp knife.

Treatment of harmful rust

1. Brush lightly with toothbrush and high-concentration washing powder water (soak in warm washing powder water for 20~30 minutes before brushing, and be careful not to use acid foam).

2. After brushing, apply glycerin (the kind used to rub hands and crack in winter). Don't apply too much. Just apply a thin layer with a cotton swab, and the surface will look shiny ~!

3. After brushing, put it in a dry place for half a month, and then take it out for observation (if the oil on the surface is dry, brush it again and repeat it three times is the best).

4. After the second glycerin coating, apply a thin layer of sewing machine oil for maintenance. In this way, harmful rust will not continue to infringe on the money body.

Remember to apply glycerin for the first three times, because glycerin contains organic ingredients, which can protect money. If you apply sewing machine oil from the beginning, it is easy to damage the patina of coins.

6. The reason for blistering with warm washing powder is that the washing powder contains alkali. Under the action of warm water, the activity of alkali increases, which can make rust more stable, no longer react, and play a stabilizing role!

The above six methods are the experience summed up in dealing with rust, so you can try them. But remember, you must first apply oil containing organic ingredients, because that plays a key role-protecting the patina of coins. Glycerol, cod liver oil and snake oil are all acceptable, and cod liver oil is the best.