I'm sure you're aware of the properties of the spongetech sponge, since being a simple sponge, spongebob would also re-absorb some of that used soap even if you rinsed it. Just using any sponge it is impossible to keep it from sucking up and holding the dirty stuff. That's why the claim of clean multi uses doesn't hold, um, SOAP. The very nature of a sponge makes that impossible.
If spongebob has enough soap for 5 or whatever washes, how many are last washed reabsorbed soap. If you keep squeezing to where you THINK the sponge is clean, haven't you wasted a whole bunch of internal soap. Notice this observation never gets mentioned in the spng media or the longs postings.