Regarding the Oxi soaking (which works miracles) here are a couple of things to note - if your shirts have MOP buttons, skip the vinegar soak. It eats away at them leaving them dull lacking iridescence. I'd particularly skip this step if you plan on re-selling the shirts. I think the primary ingredient in this stain removing process is the Oxi rather than the vinegar. Also, if you don't already, wear gloves when working with the concentrated Oxi solution. That shit will mess up your hands.