Clean parasite (6)
I believe the answer is:
sponge
I believe this is a double definition.
'clean' is the first definition.
(I've seen this before)
'parasite' is the second definition.
(term for someone getting something from others)
(Other definitions for sponge that I've seen before include "No pegs on this substance to soak up" , "Bathroom scrubber" , "Marine animal with ability as at 3 Down" , "Sea creature - cleanser - cake" , "Cadger" .)