Sponges:  Put them in the dishwasher (top rack) whenever you run the dishwashe; when the dishes are done and the sponge is still wet, put it in the microwave for 30-45 seconds.  Be careful taking them out, as they'll be burning hot.  This not only sterilizes the sponges, but keeps them sweet-smelling too.

I use paper towels for drying my hands unless I've just washed dishes by hand, in which case my hands are clean and I just dry them on the dish towel.  I have to admit, though, that I don't change my dish towel as often as I probably should.  So I guess I have completely sterile sponges and slightly dirty towels, lol.

Ruth