Even if you have deleted the files on your Android smartphone, they can be easily recovered by attaching the phone to a Windows computer and running a tool like Recuva. One of the ways to prevent the file recovery is to securely erase the files using an app like Remo File Eraser that overwrites the files with random data before deleting them. But what about the files that you have already deleted? In order to securely overwrite the already deleted files from the free space in your Android smartphone, you can use the free Secure Wipe app.
The Secure Wipe app for Android is a small, simple and straightforward solution for wiping the free space. This app is for using for securely wiping the free space and not for wiping the existing files. It can erase the free space on the Android system partition, internal SD card and the external SD card.
After launching the Secure Wipe app, it will show you the free space available on the system, internal and external SD cards. It shows a list containing the number of total memory blocks, available free blocks and the size of these free blocks. You can select what type of memory you want to wipe – system space, primary SD card (internal SD card) and the secondary SD card (external SD card). Tapping on the Start Wiping button shall start the wiping process after showing a warning dialog.
The process may take a long time depending on the size of free space available on your Android smartphone. On my 8 GB external SD card which had around 7 GB of free space available, it took nearly 20 minutes to finish the sanitizing of the free space.
Conclusion: The Secure Wipe app can completely overwrite and remove the data belonging to the already deleted files from your Android smartphone. It can securely sanitize the free space from your Android system memory, internal and external SD cards.
You can download the Secure Wipe app for Android from https://play.google.com/store/apps/details?id=com.pinellascodeworks.securewipe.