Well, the sponge itself would be rinsed of fecal matter in running water, and the salt water/vinegar soak would have taken care of the rest. Smell (at least, the smell of the wiped Romans) wouldn’t have been a problem - transmission of parasite eggs from fecal matter, on the other hand? Probably a non-negligible issue.
I have to wonder if this means that all the ancient Romans kind of smelled a little poopy all the time
Well, the sponge itself would be rinsed of fecal matter in running water, and the salt water/vinegar soak would have taken care of the rest. Smell (at least, the smell of the wiped Romans) wouldn’t have been a problem - transmission of parasite eggs from fecal matter, on the other hand? Probably a non-negligible issue.
https://www.livescience.com/53303-ancient-rome-infested-with-parasites.html
It was pretty bad.