Develops hard outer layer because they're rejected so often by children? (6)
I believe the answer is:
crusts
'because they're rejected so often by children?' is the definition.
The definition suggests an adverb but the answer is not.
'develops hard outer layer' is the wordplay.
'develops hard' becomes 'crus' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'outer' says to hollow out the word (remove centre letters).
'layer' becomes 'tights' (I have seen 'layer of clothing' mean 'tights' so perhaps 'layer' could also mean 'tights').
'tights' with its centre taken out is 'ts'.
'crus'+'ts'='CRUSTS'
Can you help me to learn more?
(Other definitions for crusts that I've seen before include "Hard surface layers" , "Edges of bread" , "Hard coverings, of bread say" .)