Once you reach level 85, the Real Holy Grail can be found by searching for gems. The Grail is activated by dragging and dropping it onto your profile picture. With a solemn animation, the game confirms the activation.
From now on, it will be much easier for you to discover missing items from your scrapbook in the hall of fame: While items already found are not highlighted, missing items will literally pulsate. This is the indicator that the "flashing" item is still missing in your scrapbook.