Hitchhiking is illegal in many states but when it was done quite abundantly, I remember being younger, under 10 so this was late 70s/early 80s, and my dad picked up a hitchhiker or two and they were no problem.
As a hypothesis, I would say months easily... it would really depend on how often...
DNA tests are VERY expensive so I don't think you will ever find any that are free. If you really want to know, report the item to the police and let them do the testing and figure out whatever it is.
DNA tests are VERY expensive so I don't think you will ever find any that are free. If you really want to know, report the item to the police and let them do the testing and figure out whatever it is.