Find a very small amount (5)
I believe the answer is:
trace
I believe this clue is a double definition.
'find' is the first definition.
(I know that trace is a more specific form of find)
'a very small amount' is the second definition.
(I've seen this before)
(Other definitions for trace that I've seen before include "Make a copy using transparent paper" , "Cater (anag.)" , "suspicion" , "Skimpy garment" , "Evidence" .)