Deleting files on an old USB drive isn’t enough; it only marks space as free, and recovery tools can retrieve the data. An old flash drive with tax records or scanned IDs becomes a privacy risk if it falls into the wrong hands. A full format is recommended because it scans for bad sectors and overwrites existing data, making recovery harder.

According to Cornell University IT security guidance, functional drives for recycling should be overwritten 3 times, while drives to be disposed of should be physically destroyed. A full format takes longer than a quick format but offers greater security.

You can format the drive on Windows by opening File Explorer, selecting This PC, right‑clicking the device, and choosing Format while leaving Quick Format unchecked. On a Mac, open Disk Utility, select the drive, click Erase, and optionally expand Security Options to set overwrite passes. Third‑party tools like DBAN or Shred OS can add extra passes, but for highly sensitive data physical destruction remains the safest choice.

To destroy the drive, crack open the enclosure and damage the memory chips with a chisel, Dremel, or drill, taking care to avoid flying fragments. After wiping and destroying, recycle the device at an authorized e‑waste facility or through retailer take‑back programs.