Fluid from bottles maybe working, drip returned (4)
I believe the answer is:
vino
'fluid from bottles maybe' is the definition.
('wine' in Italian)
'working drip returned' is the wordplay.
'working' becomes 'on' (on can mean working or activated).
'drip' becomes 'IV' (intravenous drip).
'returned' shows that the letters should be reversed in order.
'on'+'iv'='oniv'
'oniv' reversed gives 'VINO'.
(Other definitions for vino that I've seen before include "Wine (slang)" , "Cheap wine" , "In - veritas means alcohol promotes truth-telling" , "Italian wine - any brand" , "Wine, colloquially" .)