The restoration and conservation of numismatics is most common in archaeological material, whether terrestrial or underwater, where mechanical methods adapted for numismatics are used to reveal the relief on the coin, from which experts can then precisely determine its origin, age and rarity. The material from which the coin is made is mostly copper and its alloys, and less so silver or alloys of silver and copper. Conservation is not too different from that applied to other objects made of the same material.