Remove coarser elements from puzzle (6)
I believe the answer is:
riddle
This clue is a double definition.
'remove coarser elements' is the first definition.
(riddle is a type of sieve or filter)
'puzzle' is the second definition.
(a riddle is a puzzle or problem)
'from' is the link.
(Other definitions for riddle that I've seen before include "sort out" , "Question to test ingenuity, something puzzling" , "Strain" , "Sieve or conundrum" , "Cryptic statement" .)