Google introduced a new great feature for Google AdWords MCC (My Client Center) users.
As you have more and more clients in your MCC interface, a few of those clients keep leaving over time, and allow to have access to their accounts. But now, the advertisers can declutter their AdWords MCC by hiding those unused accounts.
The feature says, "simply organize your views by selecting unused account(s) and then choosing Hide from the Edit dropdown."
Declutter & Hide Unused Accounts in MCC With New AdWords Feature!,