Gas almost left in property (7)
I believe the answer is:
chattel
'property' is the definition.
(chattel is a kind of property)
'gas almost left' is the wordplay.
'gas' becomes 'chat' (I've seen this before).
'almost left' becomes 'tel' (I can't justify this - if you can you should believe this answer much more).
'chat'+'tel'='CHATTEL'
'in' is the link.
Can you help me to learn more?
(Other definitions for chattel that I've seen before include "Item of non-freehold property" , "something one owns" , "Piece of portable property" , "Item of personal property" , "Personal possession" .)