Top removed from cleaning liquid for drain (5)
I believe the answer is:
leach
'for drain' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for leach that I've seen before include "Filtrate" , "Drain away by percolation" , "Remove (soluble material) by percolation" , "Drain away through percolating liquid" , "Percolate - be removed by percolating liquid" .)