When an etching agent is applied to a metal surface in order to restore a removed serial number the stamped area will dissolve at a slower rates the stamped area?

When an etching agent is applied to a metal surface, it interacts differently with areas that have been stamped, such as a serial number. The stamped area typically has a denser structure due to the deformation caused by the stamping process, which can make it less reactive to the etching agent. As a result, the surrounding metal may dissolve at a faster rate, leading to the restoration of the serial number's visibility as the etched area remains less affected. This technique can help in recovering important identification marks on metal surfaces.