Scours harbour — with nothing like a walrus to be seen? (5-6)
I believe the answer is:
Here is my best explanation:
'with nothing like a walrus to be seen?' is the definition.
(walrus moustache is a type of facial hair)
'scours harbour' is the subsidiary indication.
'scours' becomes 'cleans'.
'harbour' becomes 'haven' ('haven' can be a synonym of 'harbour').
(Another definition for clean-shaven that I've seen is "Unbearded".)