Sponges

When I was a kid, Mom taught me to soak a sour sponge in a little bleach and water and it would sweeten the sponge right up.  But that no longer works!  What have they done to our sponges?  I really like those little yellow sponges with the scrubber on the other side.  But now, they only last about 3 days before they stink and everything they touch, dishes, counters and hands, stink too.  I've tried soaking the sponges in a bleach solution which buys me about 1 extra day before I throw them away.  I know you can 'nuke' them in the microwave but that doesn't last long and I use our microwave as a breadbox.  (Really dislike microwaves and wouldn't be able to use mine if the power was off and we were using the generator anyway.)  I've never cared for dishcloths as they don't scrub as well either.  So, anyone out there know what they've done to our sponges?