If you assume the inside of your washer is the cleanest place in your home because you put detergent through it with every load of laundry, join the club. Most people think that—and that’s a really bad assumption. Have you ever wondered why there’s dirty residue on the agitator? Why do washed clothes sometimes come out with stains they didn’t have before they went in? Why do towels get stinky? The answer is germs. According to a study by Dr. Charles Gerba, professor of microbiology at the University of Arizona, if you wash a load of just underwear, there will be 100 million E. coli in the wash water, which can be transmitted to the next load of laundry. However—and this is good to know—of the more than 60,000 kinds of germs, only 1 to 2 percent of them are potentially pathogenic. But the other 98 percent, when allowed to …