Drink found in percolator (4)
I believe the answer is:
cola
'drink' is the definition.
(cola is a type of drink)
'in percolator' is the wordplay.
'in' indicates the answer is hidden within the clue.
'COLA' is hidden within 'percolator'.
'found' is the link.
(Other definitions for cola that I've seen before include "Cold drink" , "Carbonated soft drink" , "Fizzy drink" , "pop" .)