Hair cleanser (7)
I believe the answer is:
shampoo
'hair cleanser' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for shampoo that I've seen before include "Ooh, spam! (anag.)" , "Oh, so Pam uses it on her hair?" , "Soap for washing hair" , "clean" , "Hair-cleaner" .)