1, acupuncture method: press the patina on the surface of copper coins vertically with a steel needle, and then let go quickly to see if the steel needle can stand up, because the patina that has been stored for a long time is hard and can't be stabbed.
2. Cooking method: Boil the coins in boiling water for 15 minutes, and pick them up to see if there is any change. If there is no change, they will be true, because some counterfeiters may attach clay and other items to their watches to make them look realistic, but after boiling, the surface will fall off.
3, observe the copper color method: the copper of ancient money mainly includes red copper, bronze, brass, white copper and so on. Red copper has the highest copper content, generally above 90%, and its color is purplish red. Bronze belongs to Cu-Sn-Pb alloy, and its colors are crimson, reddish or aquared, bluish white and yellowish. Brass refers to copper-zinc alloy, which is divided into light yellow and golden yellow. White copper refers to copper alloy, which is more common in modern machine-made coins. There are some copper-colored silver-white square-hole ancient coins, also called white copper coins, but they actually contain no or little. It is also a kind of bronze, but there are more components of lead and tin, which causes the change of copper color. In order to respect the habit and facilitate identification, it is still called white copper coin. Moreover, before the Ming Dynasty (including the late Yuan and early Ming Dynasties), there was no brass due to the limitation of alloy technology, so all the brass money before the Ming Dynasty was fake.
There are many other methods, but the above three methods can be judged, so I won't go into details.
The identification method of silver coins is attached.
The first method is to "knock", take two silver coins, hold the center of a silver coin with the fingertips of both hands, and slowly move closer. When two silver coins overlap by about a quarter, the two silver coins gently tap the edge of each other, and the sound of real coins is crisp and the sound of counterfeit coins is dull.
The second method is to "blow", gently hold the center of the silver dollar with your index finger and thumb, suddenly blow up the vertical edge of the silver dollar and put it to your ear quickly. Silver coins with really good color have a long and clear ending, which other metals or non-pure silver will not have. For example, the common silver coins filled with lead in the market are almost silent, because lead is relatively heavy and soft, and it is not easy to vibrate and pronounce. Nowadays, most forgers use computers to make plates and use alloy materials to pretend to be silver. Its color and words can be confused, but in the final analysis, it is not silver, its pronunciation is sharp and long, and insiders will know the authenticity as soon as they distinguish it.
The third method is "weighing". Real money is generally heavy, and the loss after circulation is about 26 grams. Its color is moist, soft and white, the tone is soft and long, the picture and text are accurate and the patina is natural. Counterfeit money is generally not heavy enough, or overweight due to thickening, and its color is dark.
The above is my personal opinion, I hope it will help you.