I’m not putting this in GQ because I don’t think there is a singular answer.
Suppose the following hypothetical.
(1) Cut out a 12 x 12 centimeter square from an old white T-shirt.
(2) Get into a fistfight with your best friend and have him or her bleed on the cut out square.
(3) Put the square out in the air to dry for a minimum of two weeks.
Most of us know that dried blood is notoriously hard to get out of fabrics. We might get 95% just by laundry or with Woolite® or eqivalent. Most of us would be happy with 95%.
But we also know that everything migrates to an equibrium state. After laundry washing, take your cloth square and submerse it into a 55 gallon drum filled with distalled water. Agitate periodically. Leave it for a minimum of three months or as long as you like. After that period, would it be 100% free of blood contaminates?
I think yes. Certainly their would be some residual molecular blood components in there but it would be impossible to ascertain with modern equipment.