Clear salt on crack (7)
I believe the answer is:
absolve
'clear' is the definition.
(I've seen this in another clue)
'salt on crack' is the wordplay.
'salt' becomes 'ab' (I've seen this in other clues).
'on' means one lot of letters go next to another.
'crack' becomes 'solve' (crack can mean to solve or decipher).
'ab'+'solve'='ABSOLVE'
(Other definitions for absolve that I've seen before include "Set free from guilt" , "Clear of blame or quilt" , "Let off the hook" , "Forgive sins" , "Declare (someone) free of guilt" .)