1
$\begingroup$

What acid/chemical in human skin can react with stainless steel to leave a black mark on the skin? Why is it secreted/produced in larger quantities by some people and not by others?

$\endgroup$

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.