Buying used phones safely: a checklist for the counter

This guide is shop practice, not legal advice. Some countries require a licence, a register or a holding period for second-hand goods. Ask your local authority or your lawyer what applies to you.

1. Match the IMEI in three places

Dial *#06# and compare the number on the screen with the one in the phone's settings, the one printed on the SIM tray or the back, and the one on the box if the seller has it. They should all agree. A box with a different IMEI is just a box. A phone whose printed IMEI differs from the one on the screen has had its housing or its board changed: price it as that, or walk away. A dual-SIM phone shows two IMEIs. Write down both.

2. Have the account lock removed in front of you

A phone still tied to the seller's account is useless to the next owner: after a reset it asks for that account again. Don't accept "I'll send you the password later". Ask the seller to do four things while you watch:

1. Sign out of their account on the phone (the Apple account on an iPhone, the Google account and the maker's account on Android).
2. Turn off the find-my-device feature.
3. Erase the phone from its settings.
4. Let it start up again, and go through the set-up screens yourself until you reach the home screen without being asked for the previous owner's account.

If the seller can't do that, don't buy the phone. Then put in a SIM from a network other than the seller's and make a call. That tells you the phone isn't locked to one carrier and that it actually connects.

3. Ask whether it has been reported lost or stolen

In some countries the carriers or the telecom regulator offer a way to check an IMEI against a list of lost and stolen devices. Where that exists for you, use it and note the result on the purchase note. Where it doesn't, the seller's ID and signature in steps 6 and 7 are your protection.

4. Test it like a repair, before you pay

• Screen: lines, dead spots, a burnt-in image, and touch across the whole surface. Drag an icon into every corner.
• Battery health in the settings. A battery in the low 80s or below will need replacing before long. Take the price of a battery off your offer.
• Cameras front and back, the flash, the speaker, the earpiece and the microphone. Record a voice note and play it back.
• Buttons, vibration, fingerprint or face unlock, Wi-Fi, Bluetooth and charging, with your own cable.
• Liquid: the indicator inside the SIM tray slot, green or white deposits in the charging port, mist under the camera lens.
• Earlier repairs: screws that don't match, a screen that sits higher than the frame, a gap along the edge. On some phones the settings say when a part has been replaced.

5. Grade it the same way every time

Use a short scale and stick to it: A for no visible marks, B for light marks, C for clear wear or a replaced part. The grade and the battery health set what you pay today and what you can ask tomorrow, and they are what the next buyer will hold you to.

6. Know who you are buying from

Ask for the seller's ID, check the name and the photo, and write the ID number on the purchase note. A seller who won't show one has told you what you needed to know. Slow down when you see any of these:

• a sealed phone offered far below the market price;
• a seller who doesn't know the passcode;
• several phones from one person who isn't a trader;
• a seller in a hurry who won't wait for the checks.

7. Write a purchase note, and have it signed

One page is enough. It carries the date; the seller's name, ID number and phone number; the phone's brand, model, storage, colour and IMEI; its grade and battery health; what came with it; the price and how it was paid. Above the signature, one sentence: the phone belongs to the seller, it is not reported lost or stolen, and every account has been removed from it. Keep a copy. If anyone ever comes asking about that phone, this page is your answer.

8. Pay in a way that leaves a record

Record the payment against the purchase: who was paid, how much, from which drawer. On a trade-in, show the old phone's value as its own figure against the new one, not as a discount nobody can explain later. How used phones are taxed differs by country, so ask your accountant. The VAT guide has the questions to ask.

9. Erase it again before it goes on the shelf

Erase the phone yourself once more, even though the seller did it in front of you. No previous owner's photos should ever reach the next customer. Then put the grade, the battery health and your warranty on the price tag and on the invoice, with the IMEI. A buyer who knew it was grade B at 86% doesn't come back angry.

How SolderDesk does this

In SolderDesk a used phone bought from a customer, as a buy-back or a trade-in, goes into stock as its own item under its IMEI, with its grade and battery health. The IMEI is checked as you type, so a wrong digit is caught at the counter. When the phone is sold, the invoice prints the IMEI and the warranty.

SolderDesk keeps the record. It does not check an IMEI against a list of stolen phones, and it cannot tell whether an account lock is still on, so the checks above stay with you. Try it free.