Cleaner fluid into outlying grate (7)
I believe the answer is:
janitor
'cleaner' is the definition.
(thesaurus)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for janitor that I've seen before include "One employed to clean and maintain a building" , "Caretaker (mainly US)" , "Person looking after building" , "(In Scotland) school caretaker" , "Caretaker or doorkeeper" .)