Use river with bit of salt water (4,3,4)
I believe the answer is:
wear and tear
'use river' is the definition.
'wear and tear' can be an answer for 'use' (thesaurus). I'm not sure about the 'river' bit.
'with bit of salt water' is the wordplay.
I cannot quite see how this works, but
'with' could be 'and' and 'and' is located in the answer.
'bit' could be 'ear' (I have seen 'Bit of corn' mean 'ear' so perhaps 'bit' could also mean 'ear') and 'ear' is found within the answer.
an anagram of 'water' is 'wtear' which is located in the remaining letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for wear and tear that I've seen before include "Deterioration in normal use" , "Natural deterioration" , "Depreciation" , "Two examples of running water" , "Gradual damage" .)