How to clean an Android phone: complete cleaning before selling or optimizing

Wiping a smartphone on Android is not just deleting unnecessary files, but a complex procedure that can pursue different goals. Someone wants to prepare a device for sale so that new owners do not gain access to personal data. Others seek to restore the phone to its former speed by removing the accumulated digital junk. And some are faced with the need to reset after virus attacks or system failures. In any case, incorrect actions can lead to the loss of important data or even failure of the device.

In this article we will look at all cleaning methods - from superficial cleaning of the cache to complete erasure of data with encryption, which excludes the recovery of information even by specialized apps. We will pay special attention to the nuances for different versions Android (from Android 10 to Android 14), and we will also tell you how to get around common errors due to which users lose photos, contacts or account passwords. If you are planning to sell your phone, transfer it to another person, or just want to start with a clean slate, these instructions will help you do everything right.

Preparing for cleaning: what you need to do before resetting

Before you start stripping, it is necessary to save all important data. Even if you are sure that there is nothing valuable on the phone, check again: users often forget about saved passwords in the browser, message history in instant messengers, or application backups. Here's what you definitely need to do:

• 📱 Create a backup copy contacts, photos, videos and documents. Use Google Drive, Yandex Drive or physical storage (computer, external SSD).
• 🔑 Export passwords from browsers (Chrome, Firefox) and password managers (1Password, KeePass).
• 📱 Synchronize application dataif they support cloud saving (for example, WhatsApp, Telegramgames with progress).
• 📋 Write down the IMEI phone (dial *#06# in the dialer) - you will need it to block the device if lost.

If you clean the phone before selling, additionally:

• 🛒 Delete all bank cards applications (SberBank Online, Tinkoff, Google Pay) and unlink the cards.
• 🔄 Log out of all accounts (Google, Samsung, Mi Account etc.) so that the new owner does not gain access to your data.
• 📡 Disable Find My Device (or a similar function from the manufacturer) - otherwise the new user will not be able to activate phone.

⚠️ Attention: If you use Samsung Knox, Huawei Mobile Services or other proprietary security systems, after resetting you may be required to enter the login/password from the manufacturer's account. Make sure you remember this data!

Cleaning methods: from superficial to deep

Depending on the purpose, you can choose one of three cleaning levels. Each of them has its pros and cons:

Let's look at each method in more detail.

1. Superficial cleaning (without resetting)

This method is suitable if the phone starts to slow down, but you don’t want to lose data. It includes:

• 🧹 Clearing application cache (in Settings → Storage → Cache data).
• 🗑️ Removing unnecessary files via built-in File manager or Google Files.
• 🔄 Optimizing startup (disabling background processes in Settings → Applications → Autostart).

For automatic cleaning, you can use utilities like CCleaner or SD Maid, but be careful: some of them aggressively delete data, which can disrupt the operation of applications.

2. Factory reset

This is a standard way to return the phone to its original state. It deletes:

• 📱 All installed applications and their data.
• 📁 Personal files (photos, videos, music).
• ⚙️ User settings (wallpaper, sounds, network settings).

How to reset:

1. Open Settings → System → Reset settings (the path may differ depending on the shell).
2. Select Delete all data (reset to factory settings).
3. Confirm the action (you may need to enter a PIN code or pattern).
4. Wait for completion (phone will reboot several times).

⚠️ Attention: On some phones (for example, Xiaomi or Realmeafter resetting, you need to re-link the manufacturer's account. If you have forgotten the password, the device may be locked!

3. Full erase with encryption

This method is used when you need to ensure that data is permanently deleted. It is suitable for corporate phones or devices with confidential information, here the memory is overwritten with random data (usually in 1-3 passes).

How to enable:

1. Activate encryption in Settings → Security → Phone encryption (connection to charging may be required).
2. After encryption, reset to factory settings (see instructions above).
3. For additional security, use specialized utilities like Secure Erase (requires rootaccess).

On phones with Android 10+ encryption is enabled by default, but resetting does not always overwrite the data. A complete wipe is recommended. use fastboot (see section for advanced users).

Cleaning for different manufacturers: nuances and differences

The reset procedure may differ depending on the brand and shell Android. Let's look at the features for popular manufacturers:

Samsung (One UI)

On phones Samsung the reset is performed via Settings → General management → Reset. data-i="145">Settings → General management → Reset

• 🔄 Requires re-entering account data Samsung (even if you logged out before resetting).
• 🛡️ Knox can block the device if it was stolen (checked by IMEI).
• 📱 For complete cleaning, use the mode Download Mode (press Volume Down + Power, then connect to the PC and perform factory reset via Odin).

Xiaomi (MIUI)

Xiaomi known for strict binding to account Mi Account. When resetting:

• 🔒 If the phone was linked to an account, after resetting you will need to enter your login/password.
• 🛠️ To bypass the blocking (if you have forgotten the data), you need EDL mode an official unlocker from Xiaomi.
• 📦 In some models (Redmi Note 10 and newer), the reset does not delete data from SD cards —it needs to be formatted separately.

⚠️ Attention: On Xiaomi s MIUI 12+ after 3 unsuccessful attempts to enter the account password, the device is blocked for 72 hours. Be careful!

Google Pixel (Stock Android)

Phones Pixel offer the “cleanest” Android, but there are nuances here:

• 🔄 Reset is performed after Settings → System → Reset parameters.
• 🛡️ After the reset, it automatically turns on Factory Reset Protection (FRP) - you will need to enter the data of the last synchronized account Google.
• 📱 For complete cleaning, use fastboot with the command fastboot erase userdata (an unlocked bootloader is required).

Huawei (EMUI/HarmonyOS)

On devices Huawei reset is complicated by the lack of services Google:

• 🔧 Path to reset: Settings → System and updates → Reset.
• 🔒 After the reset, you will need to enter your account data Huawei ID.
• 📡 If the phone was working on HarmonyOS, some applications may not be restored from the backup Google.

Cleaning through fastboot i ADB: for advanced users

If a standard reset did not help or you want to be sure to erase data, you can use developer tools - fastboot i ADB. This method requires command line skills and is suitable for:

• 🔧 Devices with an unlocked bootloader (bootloader).
• 📱 Phones where a standard reset does not work (for example, due to damaged firmware).
• 🛡️ Advanced cleaning with overwriting memory.

Instructions for fastboot:

1. Install Android SDK Platform-Tools on PC (official website).
2. Connect the phone in mode fastboot (usually press Volume Down + Power with the device turned off).
3. Open the command line in the folder with platform-tools and execute:

fastboot devices # Checking the connection
fastboot erase userdata # Delete user data
fastboot erase cache # Clear cache
fastboot reboot # Reboot

To completely overwrite memory (analogue Secure Erase):

fastboot format userdata

⚠️ Attention: Commands fastboot erase and fastboot format irrevocably delete the data. If you make a mistake with the section (for example, instead of userdata enter system), the phone may stop loading!

For cleaning via ADB (if the phone turns on, but you need to delete data without resetting):

adb shell
su
rm -rf /data/*
rm -rf /cache/*

This method requires rootrights and may break the system. Use it only if you understand the risks.

Install Android SDK. Platform-Tools|Unlock the bootloader (if necessary)|Make a backup|Connect the phone in fastboot mode|Check the fastboot devices command-->

What to do after cleaning: check and configuration

After a reset, the phone returns to its factory state, but this does not mean that it is ready for use:

• 🔍 Check the storage: open Settings → Storage and make sure that all data is deleted. If there are files left (for example, on SD card), format it separately.
• 🔄 Update the firmware: go to Settings → System → Software Update and install the latest security patches.
• 🛡️ Set up security:
  • Enable Find My Device (for Google) or a similar manufacturer function.
  • Set a PIN code or pattern.
  • Activate encryption (if it is not enabled by default).
• 📱 Restore data: If you made a backup, transfer contacts, photos and applications back. Use Google Drive or Smart Switch (Samsung).

If the phone was wiped before sale:

• 🛒 Check the IMEI: dial *#06# and compare with the previously recorded number. If the IMEI has changed, the phone could be restored after blocking (such devices are often sold by scammers).
• 🔋 Charge the battery to 50–80% - this is a standard requirement when selling.
• 📋 Draw up a transfer certificate indicating the serial number and IMEI (in case of disputes).

If after resetting the phone is slow or glitchy:

• 🔄 Try it repeat the reset (sometimes the first time is incorrect).
• 🛠️ Check the firmware for updates.
• 📱 If the problem remains, the memory may be faulty (eMMC or UFSIn this case, only this will help). repair.

Common mistakes and how to avoid them

Even experienced users sometimes make mistakes when cleaning their phone. Here are the most common ones and ways to prevent them:

• 🚫 An unmade backup. Many people forget to save call history or application settings. Use SMS, call history or application settings. Use SMS Backup & Restore or built-in tools (Smart Switch for Samsung).
• 🔒 Forgotten manufacturer account. On Xiaomi, Huawei or Samsung after a reset, you may be required to enter a login/password from Mi Account, Huawei ID or Samsung Account. If you do not remember the data, the phone will become a "brick".
• 📱 Incomplete reset. On some phones (for example, LG or Sony) Resetting through the settings menu does not clear SD card or the internal memory completely. Always check the storage after the procedure.
• 🔋 Reset when the battery is low. If the phone turns off during cleaning, this may cause damage. firmware. Charge the battery to at least 50%.
• 🛡️ Ignoring FRP (Factory Reset Protection). On Android 5.1+ After the reset, you are required to enter the last account data GoogleIf you do not remember the password, the phone will be locked.

How to avoid problems:

• 📝 Write down all logins/passwords from manufacturer accounts and Google.
• 🔋 Connect the phone to charging before resetting.
• 🔍 Check your phone model before using custom tools (for example, fastboot or Odin). Some commands may not work on certain chipsets (Qualcomm, Mediatek, Exynos).

FAQ: answers to frequently asked questions

adb shell
su
rm -rf /data/ /cache/