Clean out natural gas producer! (3)
I believe the answer is:
gut
I believe this clue is a double definition.
'clean out' is the first definition.
(thesaurus)
'natural gas producer' is the second definition.
(your gut produces gases)
(Other definitions for gut that I've seen before include "Belly; instinctive (feeling)" , "Cologne's good" , "Part of the digestive system" , "Evidence of heavy drinking" , "Internal channel" .)