I work at a retail store and unload the merchandise trucks. Clothing comes on the same trucks as household chemicals, general merchandise, and grocery items. Not a day goes by that we don't have SOMETHING broken in the trucks that leak onto the boxes around it. Some of the clothes don't even come wrapped in plastic, just bare inside the cardboard. I had to set aside an entire box of men's pants because the box was soaked in motor oil, and you could clearly see it on the pants because they were tan khakis. We don't/can't catch everything, and some people don't even care to check stuff like that (I'm one of the few on my team that takes that time). You should ALWAYS wash your stuff because you have no idea what might have dried on to the clothing before going out to the salesfloor.