Creature said to be used in bleaching (5)

I believe the answer is:

leech

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'creature' is the definition.
(leech is a kind of creature)

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

(Other definitions for leech that I've seen before include "and one of his remedies" , "Blood-sucking parasite" , "Worm - sponger" , "Blood-sucking worm or parasitical person" , "Clinging type" .)

I've seen this clue in the Evening Standard.

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