Not to be swallowed, even after removing first couple of crusts (8)
I believe the answer is:
inedible
'not to be swallowed' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for inedible that I've seen before include "needing to be taken off table?" , "Unpalatable" , "Not suitable as food" , "not course material?" , "Uneatable" .)