Brute concealing old record is to put things straight (9)
I believe the answer is:
apologise
'put things straight' is the definition.
(I've seen this before)
'brute concealing old record is' is the wordplay.
'brute' becomes 'ape' (ape is a kind of brute).
'concealing' means one lot of letters goes inside another.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'record' becomes 'log' (logging is a kind of recording).
'o'+'log'+'is'='ologis'
'ape' enclosing 'ologis' is 'APOLOGISE'.
'to' is the link.
(Other definitions for apologise that I've seen before include "Say sorry, my mistake" , "Say one is sorry" , "Say sorry, my fault" , "Show regret" , "Recognise fault" .)