Box of vital personal treasures (5)

I believe the answer is:

chest

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'box' is the definition.
(I know that chest is a type of box)

I cannot understand how the rest of the clue works.

(Other definitions for chest that I've seen before include "Strong box; thorax" , "Strongbox; sternum" , "Bra on it" , "Coffer; trunk" , "Part of body; storage box" .)

I've seen this clue in the Evening Standard.

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