Scents, extremely old, belonging to us (6)
I believe the answer is:
odours
'scents' is the definition.
('odour' can be a synonym of 'scent')
'extremely old belonging to us' is the wordplay.
'extremely' suggests removing the centre (only the extremes of the word are used).
'belonging to us' becomes 'ours' (I've seen this before).
'old' with its centre taken out is 'od'.
'od'+'ours'='ODOURS'
(Other definitions for odours that I've seen before include "Smells of any kind" , "Smells, usually unpleasant" , "bouquets" , "Distinctive smells" , "for the nose to detect" .)