Soap doesn't kill germs, it simply makes it easier to wash germs off by making water fit into smaller areas. So, a damp sponge is a perfect environment for gro

Soap doesn't kill germs, it simply makes it easier to wash germs off by making water fit into smaller areas. So, a damp sponge is a perfect environment for growing bacteria. Now if you are using antibacterial soap your sponge may be fine like that, but then those soaps have concerns of their own (eg. They kill good bacteria that we apparently want to keep around)