I don't use sponges. I purchased bulk 50 micron polishing felt filter (it was on sale at the time, so that had a lot to do with the 50 micron size), and cut pieces about the size of a sponge. I don't share between tanks, and there's plenty to have several "sheets" per tank, with quite a lot more left over to cut up later when I wear these out.
I rinse them out when I'm done cleaning the tank with
tap water, then just hang them over the edge of the bucket to dry.
Since they aren't as thick as a sponge, they fit into crevices in the filters better. They work great for wiping down the inside of the glass, edges of the rim, etc. I don't know if I'd use them on acrylic tanks without testing an inconspicuous spot, as it might scratch.
And, with the felt filter, you don't have to worry if you're going to get a sponge that's been treated with something. You know it's aquarium safe.