To recollect is to remember. You might struggle to recollect your high school French but have no trouble recollecting every ingredient in your dad's cinnamon roll recipe.
If you ask your grandfather to recollect his experiences in high school, you want him to remember some great stories from his youth. The Latin root word, recolligere, means "to collect again," from the prefix re, "again," and colligere, "gather or collect." You can think of recollect as meaning "to gather again from your memory."