To microwave a sponge, you can follow these steps:

1. Wet the sponge and squeeze out excess water.
2. Place the sponge on a microwave-safe plate or dish.
3. Microwave the sponge for 2 minutes on full power.
4. Remove the sponge carefully from the microwave using oven mitts or tongs.

If you're microwaving a kitchen sponge that is thicker than standard sponges, you can microwave it for three to four minutes to make sure you disinfect it properly. You can also add a few minutes if your sponge is smelly.