Remove surplus empty chest (7)
I believe the answer is:
extract
'remove' is the definition.
(I've seen this before)
'surplus empty chest' is the wordplay.
'surplus' becomes 'extra' (synonyms).
'empty' says to hollow out the word (remove centre letters).
'chest' with its centre removed is 'ct'.
'extra'+'ct'='EXTRACT'
(Other definitions for extract that I've seen before include "Short excerpt" , "Draw out - distillation" , "essence" , "Short piece" , "Passage selected from a larger work" .)