Can copper coins change color when stained with salt?

Copper coins contain copper and iron, mainly copper. The main components of salt are sodium chloride and other components. Copper coins stained with salt will grow rust, corrode the iron inside, make copper coins have holes and destroy the appearance of copper coins.

Copper coins dipped in salt water will form a miniature chemical reaction container. There are copper ions, iron ions on the surface of copper coins, sodium chloride and chloride ions in brine, etc. After a long time, a chemical reaction will be formed, and the generated copper chloride is blue-green.

Ferric chloride is yellowish brown.

If the copper coins are stained with salt, they should be washed with clear water in time, dried with a hair dryer and stored in a sealed acrylic box.