How to properly clean an Android smartphone: from cache to viruses

Has your Android smartphone started to slow down, run out quickly, or show “Not enough memory” errors? The reason in 90% of cases lies in the accumulated digital garbage: remnants of deleted applications, a full cache, duplicate files and background software that you have not used for a long time. But simply deleting a few apps is not enough for deep cleaning.

In this article you will find step-by-step guide how to clean up all types of contamination - from the system cache to hidden folders with garbage, and also learn how to avoid common mistakes that lead to data loss or slowing down your phone even more. The methods are suitable for devices Samsung Galaxy, Xiaomi Redmi/POCO, Honor, Realme and other brands based on Android 10–14.

We will pay special attention hidden Android mechanisms that most "instructions" ignore: for example, how to properly clear a folder /data/local/tmp or why you shouldn’t delete the system application cache through ADB without preparation. Let's start with the safest - manual cleaning, and then move on to advanced methods.

1. Preparing to clean up: what you need to do before you begin

Before you begin deleting files, take three critical steps. If you skip them, you risk losing contacts, photos, or even blocking your phone.

• 📱 Create a backup copy. Use Settings → Google → Backup or third-party services like Titanium Backup (requires root). It is especially important to save:
  • SMS and call history (applications like SMS Backup & Restore)
  • Wi-Fi and Bluetooth device settings
  • Game data (via Google Play account or Helium)
• 🔋 Charge the phone to at least 50%. Interrupting cleaning due to discharge may damage system files.
• 📡 Connect to stable Wi-Fi. Many methods (for example, resetting the cache via Recovery) require downloading additional data.

If you plan to use ADB or root access, check whether developer optionsare unlocked on your device. To do this, go to Settings → About phone → Build number and tap on it 7 times. The message “You have become a developer” will appear.

⚠️ Attention: On devices Xiaomi and Redmi after activating the developer mode, you must additionally enable USB debugging and OEM unlocking in the menu For developersWithout this, the commands ADB will not work. work.

2. Clearing the cache: what can be deleted and what not

Caches are temporary files that applications create to speed up work. Over time, they accumulate and take up gigabytes of memory. But. you need to delete the cache selectively (selectively), otherwise some apps will start to work slower or require re-authorization.

2.1. Clearing the cache of individual applications

The safest way:

1. Open Settings → Applications.
2. Select an application (for example, Instagram or Google Chrome).
3. Tap Storage → Clear cache.

For mass clearing, use the built-in tools:

• 🧹 On Samsung: Settings → Device maintenance → Storage → Clean.
• 🧹 On Xiaomi/Redmi/POCO: Security → Cleaning → Garbage.
• 🧹 On "clean" Android: Settings → Storage → Free up space.

2.2. System cache: when and how to clear

System cache (/cache) contains update data, temporary kernel and firmware files. Cleaning it helps with:

• Freezes after updating Android.
• Errors like "The application has stopped." X stopped."
• Slow system loading.

To clean:

1. Turn off the phone.
2. Hold Power button + Volume up (on some models Samsung — Power + Bixby + Volume up).
3. In the menu Recovery select Wipe cache partition (control - volume buttons, selection - power button).
4. After completion, reboot (Reboot system now).

⚠️ Attention: Do not confuse Wipe cache partition with Wipe data/factory reset! The second option will completely reset the phone to factory settings.

Make a backup of important data|Charge the phone >50%|Remember account passwords (after cleaning, you may need to re-enter them)|Check the free space (there should be at least 1 GB)-->

3. Removing unnecessary files and duplicates

On average, an Android user stores 2–5 GB of garbage in the form of:

• 📁 Duplicate photos (for example, from WhatsApp, Telegram and gallery).
• 🎵 Unused melodies and ringtones (folder /Ringtones).
• 📄 Old documents (PDF, DOCX) from /Download.
• 🎮 Game cache (folder /Android/obb can weigh up to 10 GB!).

To search and remove garbage:

File type	Where to look	How to clean
Duplicates photo	/DCIM/Camera, /Pictures	Applications Files by Google or Duplicate Files Fixer
Downloaded files	/Download, /Downloads	Manual sorting or Settings → Storage → Files
Game cache	/Android/obb, /Android/data	Delete the game folder (first uninstall the game via Settings)
Logs and dumps	/data/log, /sdcard/log	Delete via Root Explorer (requires root)

For automated cleaning, use Files by Google:

1. Open the application and go to the tab Cleaning.
2. Select categories: "Unused applications", "Duplicates", "Large" files".
3. Click Clear XX MB and confirm deletion.

4. Optimizing startup and background processes

Many applications start when you turn on the phone and run in the background, using up memory and battery power. data-i="160">can consume up to Facebook or AliExpress can consume up to 300 MB of RAM even when you do not open them.

To disable autoloading:

• 🛑 On Xiaomi/Redmi: Settings → Applications → Autorun management.
• 🛑 On Samsung: Settings → Applications → ⋮ (menu) → Autorun.
• 🛑 On "pure" Android: use Greenify (requires root for full control).

To limit background activity:

1. Go to Settings → Applications.
2. Select an application (for example TikTok).
3. Tap Battery → Background limitation.
4. Select Limited or Optimized.

⚠️ Attention: Do not limit the background operation of system applications (for example, Google Play Services or Android SystemThis may lead to synchronization and notification errors.

What happens if you disable auto-loading of instant messengers?

When disabling autorun for WhatsApp, Telegram or Viber You won't receive new message notifications until you manually open the app. However, background RAM and battery consumption will be reduced by 15–40% (depending on the phone model).

5. Advanced cleaning: ADB and root methods

If the standard methods did not help, and the phone is still slow, it's time for deep cleaning. These methods require technical skills and can lead to loss of warranty or device inoperability if used incorrectly.

5.1. Cleaning via ADB (without root)

Using ADB (Android Debug Bridge) you can delete the cache of system applications that are usually not available for cleaning. For example, the cache Google Play Services can take up to 1 GB.

Instructions:

1. Install ADB on PC (download Platform Tools).
2. Connect your phone via USB and enable debugging.
3. Open a command line in the folder with ADB and enter:

   adb shell pm list packages -f | grep cache

   This will show applications with a large cache.

4. To clear the cache of a specific package (for example, com.google.android.gms):

   adb shell pm clear com.google.android.gms

5.2. Manual garbage removal via root

If you have root access, you can manually clean hidden folders:

• /data/local/tmp — temporary files of system processes.
• /data/log — error logs (can be deleted if the phone works stably).
• /data/dalvik-cache — virtual machine cache (clear only if there are problems with launching applications).

To do this, use Root Explorer or FX File Explorer:

1. Open a file manager with root access.
2. Go c /data or /system.
3. Delete the contents of the target folders (do not delete the folders themselves!).
4. Restart the phone.

6. Fighting viruses and malware

Viruses on Android often disguise themselves as useful applications (for example, “Memory cleaners” or “Battery boosters”) and steal data or show advertisements. infections:

• 📱 The appearance of unfamiliar icons on the desktop.
• 🔋 Rapid battery drain (even in standby mode).
• 📶 Unexpected traffic (check in Settings → SIM cards and mobile networks → Traffic usage).
• 🚫 Lock screen demanding payment (“Your phone is blocked by the FSB!”).

To scan and remove viruses:

1. Install Malwarebytes or Dr.Web Light (free versions are sufficient).
2. Run a full scan (not a quick one!).
3. Remove detected threats and reboot your phone.

If a virus is blocking the installation of the antivirus:

1. Download your phone in Safe Mode (press the power button → long tap on "Turn off" → "Safe Mode").
2. Remove suspicious applications through Settings → Applications.
3. Install an antivirus and scan the system.

⚠️ Attention: Some "cleaners" (for example, Clean Master or DU Speed Booster) themselves contain malicious code. Use only proven antiviruses from Google Play.

7. Factory Reset: When Needed

Hard Reset is an extreme measure that should be resorted to if:

• 🐢 The phone slows down even after all cleaning.
• 🦠 Viruses are not removed by antiviruses.
• 🔄 Critical errors occurred after updating Android.
• 📱 You are selling or giving the phone to another person.

How to reset:

1. Create a backup copy (see section 1).
2. Go in Settings → System → Reset settings.
3. Select Delete all data (reset to factory settings).
4. Confirm the action and wait until the reboot.

Alternative method (if the phone does not turn on):

1. Boot into Recovery (see section 2.2).
2. Select Wipe data/factory reset.
3. Confirm the action and reboot.

8. Prevention: how to keep your phone clean

To avoid bringing your phone to a state where deep cleaning is required, follow these simple rules:

• 📲 Delete unused applications once a month. Check the list in Settings → Applications → Unused.
• 🗑️ Empty the trash in the gallery and file manager (files are stored there for up to 30 days).
• 🔄 Update the software. New versions of Android have optimized memory management (for example, Android 14 a mechanism for automatically clearing the cache has been added).
• 🛡️ Do not install APK from unverified sourcesEven “hacked” games often contain them. miners or spyware.
• 📊 Monitor memory consumption via Settings → Memory or application Simple System Monitor.

For automatic optimization, configure:

• On Samsung: Settings → Device maintenance → Auto optimization (turn on the schedule).
• On Xiaomi: Security → Cleaning → Auto Cleaning (set to run weekly).

⚠️ Attention: Automatic cleaning functions (for example, MIUI Optimizer) sometimes delete necessary files, such as game saves or downloaded documents. Before activation, check what data is subject to cleaning.

FAQ: Frequently asked questions about cleaning Android

Is it possible to clear the cache of system applications (for example, Google Play Services)?

Yes, but with caution. The cache Google Play Services or Android System can be cleared through Settings → Applications, but do not delete application data (button Clear data), otherwise Google services (Gmail, Maps, Play Market) may stop working. After clearing the cache, restart the phone.

Why did the phone work even slower after cleaning?

This happens for three reasons:

1. You deleted the cache all applications, and now they are rebuilding it again, consuming resources.
2. The cleaning was superficial, and the real problem is memory fragmentation or storage wear (relevant for phones older than 3 years).
3. The virus or malware remains in the system and continues load the processor.

Solution: check your phone with an antivirus, run defragmentation (on Android 10+ it happens automatically) and monitor the work for 2-3 days. If the brakes remain, consider resetting to factory settings.

How to clear the /Android/obb folder if it takes up 10+ GB?

Folder /Android/obb stores additional game data and applications (for example, graphics for Call of Duty Mobile or PUBGTo clear it:

1. Delete games that you no longer use through Settings → Applications.
2. Open the file manager. (for example Files by Google) and manually delete folders with game names from /Android/obb.
3. If the game is still needed, but takes up too much space, try disabling HD graphics loading in its settings.

Attention: do not delete the folder obb entirely - this may lead to errors in running applications.

Do I need to clean my phone if I have 256 GB of memory and it is only half full?

Yes, even with a large amount of memory, slowdowns occur not only due to lack of space, but also for the following reasons:

• Memory fragmentation: the longer the phone is used, the more the files become fragmented, and the system takes more time to read them.
• Full cache: even with 100 GB free, 5 GB of cache can slow things down.
• Background processes: applications consume RAM regardless of the amount of permanent memory.

It is recommended to clear the cache and optimize startup once every 1-2 months, regardless of free space.

How to clear a phone before selling so that the new owners do not receive my data?

To completely clear it before selling:

1. Make a backup copy of important data (photos, contacts, messages).
2. Do factory reset (see section 7).
3. If your phone supports encryption (Settings → Security → Encryption, turn it on before resetting. This will make data recovery difficult.
4. After reset fill the memory with garbage: download a large file (for example, a movie) and then delete it. This will overwrite the memory sectors with your data.
5. Remove SIM card and memory card (if there was one).

Important: even after a reset, the data can be restored with special apps. If confidential information was stored on the phone (photos of documents, passwords), consider the option of physically destroying the drive (relevant for corporate devices).