Even though we use sponges to clean things, they are inherently dirty. We use them to clean the knives we used on raw chicken and the forks we used to scramble raw eggs. They can collect all of the worst germs. To clean your sponge, soak it overnight in a mixture of one cup of hot water, ½ a cup of white vinegar, and three tablespoons of salt. Rinse and squeeze it thoroughly the next day before using it.