Scrub computer key inside protective covering (7)
I believe the answer is:
rescind
'scrub computer' is the definition.
'rescind' can be an answer for 'scrub' (I've seen this before). I am not certain of the 'computer' bit.
'key inside protective covering' is the wordplay.
'key' becomes 'esc' ('Escape' key on a computer keyboard).
'inside protective' becomes 'rind' (I can't explain this - if you can you should give a lot more credence to this answer).
'covering' is an insertion indicator.
'esc' put into 'rind' is 'RESCIND'.
Can you help me to learn more?
(Other definitions for rescind that I've seen before include "Quash" , "undo" , "Revoke (a law/order)" , "Revoke (order)" , "Annul - discern (anag)" .)