The green powdery rust on copper coins is a problem faced by many collectors. These rusts not only affect the ornamental value of copper coins, but can also cause damage to the copper. So, what should we do with this rust?
First, we need to understand the causes of rust in copper coins. Copper coins are prone to powdery rust in a humid environment, and these rust stains can spread to other copper coins like a virus, and in severe cases, they may even penetrate deep into the copper and cause irreversible damage. Therefore, once a copper coin is found to be rusty, measures should be taken to deal with it in time.
There are several main ways to deal with green powdery rust on copper coins. One way is to use the pickling method, that is, soak the copper coin in a 10% hydrochloric acid or sulfuric acid solution for half a day to a day, then rinse it with clean water, then soak it in a small amount of alkaline water to neutralize, and finally scrub it with a wire brush and wipe it dry. This method is simple and practical, but it should be noted that strong acids can cause some damage to copper coins, which may cause discoloration of copper coins.
For slight powder rust, you can use a wire brush or copper wire brush to brush it off, and then use a brown brush dipped in white wax to rub it on the surface of the copper coin. For severe powder rust that is born with it, you can use a closed type**, that is, brush off the surface rust and then coat it on the surface of the powder rust with a kind of nitro paint to seal it.
Alternatively, toothpaste water can be used to remove the green rust from copper coins. This method involves soaking the copper coins in toothpaste water for a period of time and then rinsing them off with clean water. This method is relatively mild and causes less damage to copper coins, but the results are slower.
When dealing with the rust on copper coins, you also need to pay attention to the maintenance of copper coins. Not all patina on coins needs to be removed, especially for bronze coins, which should generally be left as intact as possible, as most of these are harmless rusts. Rust removal is only necessary when the rust seriously affects the condition and ornamental value of the coin. During the cleaning process, the strength of the acid and the soaking time should be flexibly adjusted according to the degree of corrosion of the copper coin, so as to remove the patina as much as possible without damaging the copper. Copper coins
In conclusion, dealing with the green powdery rust on copper coins requires patience and care. Whether you use pickling, brushing or toothpaste water immersion, you need to choose the appropriate method according to the actual situation and condition of the copper coin. At the same time, the treated copper coins should be stored after drying to avoid rusting again. Proper handling and maintenance can help us better preserve these historical and cultural heritages.