The safe sequence is backup, transfer and verification, account removal, built-in erasure and a final setup-screen check. Deleting photographs or apps individually is not enough.
1. Back up and verify what matters
- Confirm photographs, contacts, messages and authenticator access.
- Transfer travel cards, wallets or specialist app data where required.
- Check that the new phone can access essential accounts.
- Keep recovery codes independently.
2. Remove linked devices and accounts correctly
For iPhone, follow Apple’s current sell/trade-in sequence, including sign-out and Activation Lock removal. For Android, remove Google and relevant manufacturer accounts before factory reset so the next owner is not stopped by Factory Reset Protection. Work profiles, employer management and watches may require separate removal.
3. Use the phone’s built-in erase function
The NCSC recommends the built-in Erase All Content and Settings, Factory reset or equivalent feature. The exact route differs by device. Do not substitute manual deletion, a file-cleaner app or an unknown computer tool.
4. Verify the result
| Check | Expected result |
|---|---|
| Power on | Initial setup screen, not your home screen |
| Account request | No request for the previous owner’s Apple/Google credentials during the buyer check |
| SIM and memory card | Removed unless explicitly included |
| Trusted-device list | Updated where the manufacturer process requires it |
Faulty phones need a different risk decision
A phone that will not power on can still contain accessible data. Do not assume physical failure erased it. Ask a reputable repair or data-destruction service what can be done, and choose a recycler or disposal route that explains data handling. Avoid posting an unsafe swollen-battery phone through an ordinary service.
Related guidance: For the wider buying decision, use Buying a Phone. The Complete Phone Buying Guide brings the main costs, checks and trade-offs together.
Sources checked
Information checked on 26 July 2026. Manufacturer and platform processes can change, so confirm the current instructions for the exact device before acting.
