But a sponge? It just sits there in all of it's stagnant glory. I've heard it can be microwaved, but really, since the sponge I hate most is in the office break room, which one of my co-workers is going to be responsible for microwaving it? That's right. No one!
So I stick with my personal coffee mug and I joke about why I keep it separate from the rest of the mugs and I wash it out at the end of the day, with hot water, soap, and a surprisingly hardy paper towel, all the while that nasty sponge drips on the edge of the sink.