The outermost layer of your skin, the epidermis, naturally sheds dead skin cells. Normal friction removes some of these shed cells, but others remain in place, dulling your complexion or turning it ashy. Exfoliation helps this natural process along, using gentle friction to brush excess skin cells from the surface of your skin. Removing dead skin cells not only improves the look of your skin, it also sweeps away places where bacteria and soil could collect. Loofahs help keep your skin in good shape, but they can also harbor harmful bacteria in their many tiny holes. Like all plant matter, loofahs are also susceptible to decay if kept constantly wet, so let your loofah air dry between uses. Washing it in a mild bleach solution, after the soap is gone, could extend its useful life, but you should replace your loofah frequently. A clean loofah has a mild straw like smell; any off-putting odors means that your loofah needs to be replaced.