Collects the rags after sorting (7)
I believe the answer is:
gathers
'collects' is the definition.
('gather' can be a synonym of 'collect')
'the rags after sorting' is the wordplay.
'after sorting' indicates anagramming the letters (I've seen this in other clues).
'the'+'rags'='therags'
'therags' is an anagram of 'GATHERS'.
(Other definitions for gathers that I've seen before include "Infers" , "Assembles" , "Understands" , "Harvests" , "Gleans" .)