USE OF ACIDIFIED HYDROGEN-PEROXIDE TO REMOVE EXCESS GUN BLUE FROM GUNBLUE-TREATED CARTRIDGE CASES AND TO DEVELOP LATENT PRINTS ON UNTREATED CARTRIDGE CASES

A formula used by firearms and toolmark examiners to clean lead residu e from bullets was also found to remove excess gun blue coating from m etal cartridge cases. It consists of a mixture of acetic acid and hydr ogen peroxide and works by oxidizing the coating back into solution. T his explanation allows one to determine the optimum proportion of the mixture. Acidified hydrogen peroxide formulas were also found to ''cle an'' (oxidize or etch) metal cartridge cases in areas where there was no sebaceous latent print material (or other substances that resist ox idation). The subsequent treatment of these ''cleaned'' cartridge case s with gun blue to enhance the latent print contrast was also consider ed.