So fresh and so clean

“In fact, what little clinical evidence there is suggests that dirty soap isn’t so bad. A study from 1965 and another from 1988 used similar methodologies: Researchers coated bars of soap in the lab with E. coli and other nasty bacteria, and then gave them to test subjects for a vigorous hand-wash. Both teams found no transfer of contamination from the dirty soap. However, both studies were tainted by potential conflicts of interest: The first was conducted by Procter & Gamble, and the second came from the Dial Corp. Still, there’s no good evidence to contradict these studies, and it’s likely that the bacteria on a dirty bar would just wash off when you rinsed your hands. In other words, you’d be cleaning the soap as you cleaned your hands.” Daniel Engber, Slate Magazine