Many coin collectors know that any coin needs to be cleaned in order for it to look good. The cleaning process means not only the cleaning of surface traces of dirt, but also the removal of oxidation traces. Among aspiring numismatists, few people know how to properly clean a bronze coin while maintaining its value. Bronze is an alloy of copper with a variety of alloying additives, so bronze coins need to be cleaned in the same way as copper coins. However, there are some subtleties here.
Instructions
Step 1
Remove dirt from the coin. To do this, pour water into a glass and put a coin in it. It should lie there until the dirt gets wet. Tap water is not suitable for this purpose, so it is best to use distilled water, which can be purchased at any grocery store. When the dirt is soaked, take a soap, a toothbrush, and clean the coin in warm water. Start brushing with light pressure on the coin, then gradually increase the pressure, remembering to rinse the brush in water from time to time.
Step 2
Remove oxides from the coin. To do this, immerse it in a 5% sulfuric acid solution for several hours. With a weak presence of oxides, citric acid or a 10% solution of acetic acid can be used. If there are small inclusions on the coin, carefully remove them with a needle. In no case leave blotches, as in a short time they will show through even more and can go to other coins lying nearby.
Step 3
Rinse the coin in clean distilled water and wipe with a paper towel. Typically, after such cleaning, bronze coins lose their original patina and the appearance of the coin is poor. Apply a new layer of patina. To do this, prepare any old saucepan, pour one part of copper sulfate and three parts of potassium permanganate into it. Pour 800 ml into a saucepan. water and put it on the fire. As soon as the water boils, extinguish the fire and leave the pan on the coals. Slowly stirring the contents, dip the coins into the pan one by one. You can see the coins start to change color. Take out the coins, spread them out on the newspaper and let them dry. Finally, rub the coins with vegetable oil. Oil, when it gets into the pores, allows you to preserve the coin and prevent chlorine and moisture from entering it. This will keep the coin looking good for a long time.
