Crossword Genius

Clean up for the lubbers! (5)

Ross

I believe the answer is:

swabs

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'the lubbers' is the definition.
Although both the answer and definition are plural nouns, I cannot see how they can define each other.

'clean up' is the wordplay.
'clean' becomes 'swab' (swabbing is a kind of cleaning).
'up' becomes 's' (I can't explain this - if you can you should believe this answer much more).
'swab'+'s'='SWABS'

'for' is the link.

Can you help me to learn more?

I've seen this clue in the Evening Standard.
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