For bathing we recommend the wool sponge. It is silky soft and incredibly durable. While it is the most expensive sponge, it softness and durability make it the most popular. With proper care a wool sponge can last up to 10 years. Natural Sponges also inhibit the growth of bacteria unlike washcloths and artificial sponges. The yellow sponge is a lower cost alternative for bathing. They are not as soft and silky as a wool sponge but are soft enough for bathing and can also be used for exfoliating.