New to this Board (but not Chowhound) but have already learned a lot. Never knew you could clean sponges in the dishwasher and / or microwave. Sounds like a good idea; I'm tired of looking at a grayish sponge.
How about the scrub brush I use to clean gunk off cooking pots? It has plastic bristles and a plastic handle. Can this go in the dishwasher, upper-rack I assume?