» How to clear an SD card and erase all of its data, including the hidden junk files you can't usually delete How to clear an SD card and erase all of its data, including the hidden junk files you can't usually delete Dave JohnsonJan 28, 2021, 00:17 IST SD cards are easy to clear out using any computer.Rafi Letzter/Tech Insider You can clear an SD card by formatting it, which is the best way to free up space on a card. To format an SD card, you can use the File Explorer app on a PC, or the Disk Utility app on a Mac.