This morning on the CBS Morning Show there was a segment on the dirtiest room in our homes….the KITCHEN. To clean a sponge in the micro it was recommended to put water in a bowl, submerge the sponge and nuke for 1 minute to kill the bacteria. Cool it down, wring it out and air dry. Otherwise put it in a cup of water with 1 oz of bleach and submerge for about a minute, rinse and air dry. Air drying is important because no nasties can live in a dry sponge. Same thing for a dishrag, to soak, rinse and airdry.