I love to use sponges when cleaning my few dishes in the sink. I use my dishwasher all the time, but every now and then I have to wash out big pot or bowl or a stray glass.
Any way you know as well as I do they get smelly and it's not good to keep them around and it's just not economical to buy them if you have to keep throwing them away.
So one day I thought why not put them in my dishwasher and see how that does. Wow, it was great. Now I just pop them in there, when they aren't as fresh as I would like, and I have brand, spanking like new sponges to wash with. They are as fresh as the day I bought them.