The little dirty bits (5)
I believe the answer is:
smuts
'the little dirty bits' is the definition.
Although both the answer and definition are plural nouns, I don't understand how they can define each other.
This is the entire clue.
Can you help me to learn more?
(Other definitions for smuts that I've seen before include "signs of pollution" , "Specks of soot - South African statesman, d. 1950" , "South African field marshal and premier" , "In South Africa general" .)