Sponge on a stick, hmmm.......while there are some allusions to the use of this technique, I think a couple of pints need to be born in mind.
Sponges were luxury items, imported from the Persian Gulf. While I'm sure some toffs would be using them instead of Andrex, I'm unconvinced it was a majority pastime.
Where sponge fragments have been found in latrine strata, forensic analysis needs to be done on their content......I really wonder whether these are not tampons rather than bumwipes, considering their innate qualities and implied cost.
In the better class of communal latrine, the majority of the solids would surely have been removed with the tried and tested potsherd / hay / handful of grass, with a final poish being provided by a sponge on a stick.
To resolve these issues is why time travel MUST be invented.