1.
I just can't see her dirtying her hands in any way
2.
options for dirtying anywhere else other than the litter tray
3.
Had the creature been given a longer life-span and a more rapid method of procreation, it would have eventually spawned a new species of Quigg capable of not only cleaning things but also of dirtying things, allowing themselves to always stay alive, even if only to be caught up in a ridiculous loop of cleaning, dirtying, cleaning, dirtying, and so on
4.
They pollute their own water by dirtying it with their own feces and urine and their own bodies
5.
They wash themselves by dirtying water and then dumping the dirty water somewhere else
6.
She was afraid of dirtying it