Recovering obliterated laser engraved serial numbers in firearms

An easy procedure for recovering obliterated firearms serial numbers, which are laser engraved is presented in this case report. For these serial numbers, the traditional recovering method using acid etching generally fails, once marking the serial number does not necessarily imply a deep permanent deformation of the crystalline array. The standard required mirror-like finish of the surface commonly can destroy any evidence of the original serial number, i.e., can destroy the heat affected zone (HAZ) of only few micra, if it is still present. It is shown in this report that relief polishing and reflected light stereomicroscopy can, in certain cases, successfully reveal obliterated serial numbers, originally marked by laser. The use of this procedure for recovering this type of obliterated serial number is illustrated and discussed with an example we have dealt with.