In my younger days I used to work in a sewing factory. One place I sewed all the pockets on blue jeans and another I sewed the cotton crotch lining in underwear. By the time the end product actually goes in a box and shipped out it has been handled by maybe 30 or more people. It's been sat on, dropped in the floor, drinks spilled on them and who knows where else it's been. ANYTHING I buy gets washed before I use it. So there's another reason to prewash. OTHER PEOPLE'S GERMS