We can only imagine what icky stuff gets soaked up by the sponges we use to wash dishes, clean counter tops etc. And unless you use a new one each day (and who does that?!) I can guarantee you that there are plenty of unsavory germs that cling to that sponge. I used to throw them away, though not often enough, until someone told me to put them in the dishwasher during a cycle.
However, I just read in an old issue of Vegetarian Times that dishwasher cycle isn't the best way to clean those sponges. Researchers at the University of Florida recommend microwaving your dirty sponges to disinfect them. In their research study, they soaked some sponges in water that contained E.coli and other viruses. 2 minutes later, more than 99 per cent of the bacteria had been eliminated. Apparently, the higher temps in microwaves (as opposed to dishwashers) is what makes it a more effective way to clean sponges.
What to do:
Thoroughly wet a sponge (do not nuke dry!)
Toss it in the microwave on high for 2 minutes and voila! Nasty buggies gone, at least a good portion of them.