How to make saps disappear gradually? (4,3)
I believe the answer is:
pass off
'disappear gradually?' is the definition.
'pass off' can be an answer for 'disappear' (passing off is a kind of disappearing). I am not certain of the 'gradually?' bit.
'how to make saps' is the wordplay.
'how' becomes 'off' (I am not sure about this - if you are sure you should believe this answer much more).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'make' indicates an anagram.
'saps' anagrammed gives 'pass'.
'off' after 'pass' is 'PASS OFF'.
Can you help me to learn more?
(Other definitions for pass off that I've seen before include "Take a satisfactory course; fraudulently impose" , "Happen satisfactorily" , "Misrepresent" .)