The tersorium was shared by people using public latrines. To clean the sponge, they simply washed it in a bucket with water and salt or vinegar.This became a breeding ground for bacteria, causing the spread of disease among those using the latrines such as typhoid and cholera.

Definitely a horrendous idea and not cash money at all. I'd be carrying my own water bucket. Why not wash your ass with clean water (like India)? I'm pretty sure they also had soap then and to save soap you can also use soap water. I mean it's really not hard to have a bucket or well with soap water and use flowing water to rinse.