There are specialized machines for this that resemble industrial vacuum cleaners but even bigger. Cleaned balls are bagged and get poured back once the floor and walls are sanitized. Do the operators keep track of when this was last done? Yes, and they aren’t proud of it so you won’t see cleaning logs hanging nearby like at most mall toilets.
Thinnest Unicode whitespace. In my headcanon, the Czech language uses it as the preferred thousands separator (though some people prefer thin space, and most people just use space or nbsp) and I sometimes use it in German and English too because it’s unambiguous.
Example uses:
3 141 592 653.589
s u b t l e k e r n i n g