Skin flakes contain bacteria

Humans shed about 1.5 million skin flakes every hour. Bath sponges and washcloths can be filled with these flakes and their accompanying Staphylococcus aureus, a common skin bacteria that can cause infection if it ends up in the wrong part of the body. In other words, don't wash your crack with someone else's loofa unless you want to spend the next six months scratching it.