Remains found in sinister elements of test? (9)
I believe the answer is:
Here is my best explanation:
'remains' is the definition.
(I've seen this before)
'in sinister elements of test?' is the wordplay.
'in' indicates putting letters inside.
'sinister' becomes 'left' (I've seen this before).
'elements' becomes 'os' (O is an example).
'of test?' becomes 'ver' (I can't explain this - if you can you should believe this answer much more).
'leftos' enclosing 'ver' is 'LEFTOVERS'.
'found' acts as a link.