We bleach our sponges every use. I'm sure that won't kill everything but for the time we have them it helps. I stand them up and let them dry between uses. I try to get new ones every week or so. We mostly use cloth rags that have also been washed and bleached more often. I prefer the rags anyway. We also use the wadded plastic scrubbers to break things free. They clean up fairly easy and don't hold the bacteria as easily. Great article.