Cary Grant's real surname (5)
I believe the answer is:
leach
'cary grant's real surname' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for leach that I've seen before include "Percolate through soil or ore" , "Drain away through percolating liquid" , "Filtrate" , "Make liquid percolate through soil" , "Remove (soluble material) by percolation" .)