To better judge the state of conservation of a pen, a digital microscope can sometimes be useful.
It is often not possible for the naked eye to tell the difference between a scratch or a break, one that has maybe already been repaired elsewhere with incompatible components. Through the use of the microscope, however, this difference becomes evident. Details such as the degree of oxidization of metal parts such as rings and clips and any fractures or crystallizations of resins become evident.

 In this case the microscope highlights the oxidation state of a ring as well as a crack in the celluloid edge.

 Advanced stage celluloid crystallization.

 Initial stage celluloid crystallization.