These types of clearances are for reviewing their own records in office for consultation with current officials, and, more importantly, for writing memoirs to make money. Such clearance is never given up ‘voluntarily’.
The Clintons and the Obamas have always had that arrogant, egotistical ‘I meant to do that’ attitude no matter how disastrous or embarrassing the act. Apparently they believe it saves face but it only makes them look foolish.
Hillary in particular has tried it many times, most notably when the illegal server story broke.