The most common and most likely answer to this crossword clue is the 6 letter word KITTY*
I've seen this crossword clue in The Guardian
K
I
T
T
Y
*
Buddy explains!
The straight part
We know that "Bit of litter/pool" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bit of litter/pool = kitty*.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does KITTY* mean?
KITTY* noun- A kitten or young cat.
- (sometimes capitalized) A pet name for a cat.
- A money pool, as for a card game, or for shared expenses.
- In a home game, a small, specified amount taken from each pot to pay the host's expenses.
- Female genitals. (Euphemistic form of pussy.)
- A set of additional cards dealt face down in some games.