This document specifies a method to test for intergranular corrosion (IGC) in austenitic stainless steels using an oxalic acid etch. This method can evaluate non-sensitization of austenitic stainless steels by observing the structure of the etched surface with a microscope after performing electrolytic etching (hereinafter called “etching”) on austenitic stainless steel in an oxalic acid solution.