Sanitise unusual LA scene (7)
I believe the answer is:
cleanse
'sanitise' is the definition.
(I've seen this in another clue)
'unusual la scene' is the wordplay.
'unusual' indicates anagramming the letters.
'la'+'scene'='lascene'
'lascene' anagrammed gives 'CLEANSE'.
(Other definitions for cleanse that I've seen before include "Free of sin" , "Make free from dirt" , "Disinfect" , "Bathe" , "Make thoroughly clean" .)