Anyone who knows me, knows I am a nut about my kitchen being clean including my sponge. In professional kitchens you are required to sanitize all washed dishes. There are several ways of doing this depending upon if you are handwashing or machine washing. At the shop, since I couldn’t install a machine washer, we used bleach in the rinse water which is an approved method of sanitizing dishes, pots and pans. I have seen (but not tried) putting sponges in a microwave, dishwasher and outside in the sun. But one of the easiest, least expensive and most effective methods of not only cleaning but sanitizing is to add bleach to the water.
Kitchen sponges can not only get dirty but can be the most unsanitary thing in the kitchen. I realized I was chucking these out with great speed. So I went back to my pro days and decided to clean and sanitize in one fell swoop.
Let it sit overnight. Take it out in the morning and rinse it.