I bought a USB stick that turned out to be faulty. I deleted some personal photos from it, but recovery software can still find them. Since I'm returning the drive and it may be resold, what's the best way to erase the data so it can't easily be recovered?
3 Answers
Use the drive’s full or slow-format option rather than a quick format. You can also fill the drive with large files you don’t need and then format it again. A single overwrite is generally enough for ordinary personal data, though repeating it is an option if you’re especially cautious.
Some USB and memory-card utilities offer a full-overwrite or secure-erase mode. If the drive supports one of those functions, use it instead of a quick format. One complete pass is normally sufficient unless the data is unusually sensitive.
A dedicated drive-wiping utility can overwrite the USB stick for you. Keep in mind that flash storage uses wear leveling, so ordinary overwriting cannot guarantee that every old memory cell is erased. If the data is extremely sensitive, physical destruction is the only reliable fallback; otherwise, a full overwrite is practical for most people.

A second pass with a different file system can provide extra peace of mind, but it usually isn’t necessary for normal photos.