Cold sauce for prune (4)
I believe the answer is:
clip
'prune' is the definition.
('clip' can be a synonym of 'prune')
'cold sauce' is the wordplay.
'cold' becomes 'c' (eg on taps).
'sauce' becomes 'lip' (I've seen this before).
'c'+'lip'='CLIP'
'for' acts as a link.
(Other definitions for clip that I've seen before include "sort of joint" , "Cut short; cartridge holder" , "Extract; cartridge" , "Piece of film etc" , "Short piece of film" .)