I bought a stack of red dirt shirts in \Hawai'i which are basically stained with rust (same thing that stains in blood) and the nice shop keeper suggested if I wanted them to stay brighter to do the first washing with vinegar added. So, yes vinegar will set any iron-based stain.
1
I'll second that warning
Submitted by Emms on September 15, 2007 - 07:28.
I bought a stack of red dirt shirts in \Hawai'i which are basically stained with rust (same thing that stains in blood) and the nice shop keeper suggested if I wanted them to stay brighter to do the first washing with vinegar added. So, yes vinegar will set any iron-based stain.