To sift the remains can be something instructive (7)
I believe the answer is:
seminar
'be something instructive' is the definition.
I can't judge whether this defines the answer.
'to sift the remains' is the wordplay.
'to sift' is an anagram indicator (I've seen 'sifted' mean this).
'remains' is an anagram of 'SEMINAR'.
'can' is the link.
Can you help me to learn more?
(Other definitions for seminar that I've seen before include "University discussion" , "Group discussion of subject" , "Meeting for exchange of ideas" , "Teaching meeting, conference" , "Academic class" .)