Be a sponger, thus meriting the term 'swab'? (4)

I believe the answer is:

wipe

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''swab'?' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

(Other definitions for wipe that I've seen before include "Push cloth over" , "Cancel (tape)" , "Swab" , "Rub lightly to remove dust, etc" , "Clean with e.g. cloth" .)

I've seen this clue in the Evening Standard.

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