Wash out broken siren (5)
I believe the answer is:
rinse
'wash out' is the definition.
(thesaurus)
'broken siren' is the wordplay.
'broken' indicates anagramming the letters.
'siren' is an anagram of 'RINSE'.
(Other definitions for rinse that I've seen before include "Use water to remove soap" , "Run water through" , "Wash lightly without soap" , "Colour" , "Wash off surface dirt" .)