"I am developing a line of martial arts training tools, using 303 cold rolled round bar stock in various lengths and diameters. The metal is affecting some players more than others, in developing a black-gray oxide stain upon the palms, after a few minutes of use. I assume this to be from a unique reaction with various organic oils from the skin. My questions to the general audience are: Is there a grade of SS where this type of reaction does not occur?; Is this a common-knowledge issue with SS in skin-contact applications, with a simple remedy? Any leads or responses are greatly appreciated, as I am hoping to provide the highest quality SS training tools to my customers. Thank you for your time and consideration."