They are capable of wiping the floor with those who know how much DIRT needs to be collected (8)
I believe the answer is:
cleaners
'they' is the definition.
Both the answer and definition are plural nouns.
Maybe you can see an association between them that I can't see?
'capable of wiping the floor with those who know how much dirt needs to be collected' is the wordplay.
I cannot quite see how this works, but
'be' could be 'clean' (cleaning is a kind of being) and 'clean' is found within the answer.
The remaining letters 'ers' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'are' acts as a link.
Can you help me to learn more?
(Another definition for cleaners that I've seen is " They keep everything spotless".)