Remove Metadata from Files: MAT2 and ExifTool Guide

Every file you create carries hidden metadata — timestamps, GPS coordinates, device identifiers, author names, and software versions. A photo taken on your phone may embed your exact GPS location. A Word document might contain your name, workplace, revision history, and tracked changes. Before sharing files publicly or with unknown parties, stripping this metadata is a fundamental privacy practice.

What Metadata Can Reveal

File Type	Metadata Examples
JPEG/PNG photos	GPS coordinates, camera model, lens, date/time, software
Word/PDF documents	Author name, organization, revision history, hidden text
Audio files	Recording software, artist, album, date
Video files	Camera model, GPS, recording date, software
Screenshots	Screen resolution, OS version, software used

ExifTool: Universal Metadata Reader and Editor

ExifTool by Phil Harvey is the most comprehensive metadata tool available — it reads, writes, and removes metadata from hundreds of file formats.

Installation

Windows: Download the Windows executable from exiftool.org. Rename exiftool(-k).exe to exiftool.exe and place it in C:\Windows for global access.

Linux:

sudo apt install exiftool

macOS:

brew install exiftool

Reading Metadata

# View all metadata in a file
exiftool photo.jpg

# View specific tags
exiftool -GPS:GPSLatitude -GPS:GPSLongitude photo.jpg

# View metadata in a document
exiftool document.docx

Removing Metadata

# Remove ALL metadata from a single file
exiftool -all= photo.jpg

# Remove all metadata, keep original as backup (.jpg_original)
exiftool -all= -overwrite_original photo.jpg  # No backup

# Remove metadata from all JPGs in a folder
exiftool -all= -overwrite_original *.jpg

# Remove metadata recursively from all files in a directory
exiftool -all= -overwrite_original -r /path/to/folder/

# Remove only GPS data (keep other metadata)
exiftool -GPS:all= photo.jpg

# Remove author and company from Office documents
exiftool -Author= -Company= -Creator= document.docx

Batch Processing with Output Directory

Preserve originals while creating clean copies:

exiftool -all= -r /original/photos/ -o /clean/photos/ --ext jpg --ext png

MAT2: Metadata Anonymization Toolkit

MAT2 is purpose-built for metadata removal with a focus on privacy. It’s the tool used by Tails OS and Whonix for metadata cleaning and supports more file types than ExifTool in some categories (especially LibreOffice formats).

Installation

Linux:

sudo apt install mat2

Flatpak:

flatpak install flathub org.onionshare.OnionShare  # Bundled in some privacy tools

Basic Usage

# Check metadata in a file
mat2 photo.jpg

# Clean a single file (creates cleaned copy: photo.cleaned.jpg)
mat2 --inplace photo.jpg  # Overwrites original

# Clean without overwriting
mat2 photo.jpg  # Creates photo.cleaned.jpg

# Check what will be removed without removing it
mat2 --check photo.jpg

# Clean all files in a directory
mat2 --inplace *.jpg *.pdf *.docx

Supported File Types

MAT2 handles: JPEG, PNG, GIF, TIFF, BMP, PDF, MP3, FLAC, OGG, MP4, DOCX, XLSX, PPTX, ODT, ODS, ODP, ZIP, and more.

Nautilus Integration (GNOME)

On Linux with GNOME, install the MAT2 extension for right-click metadata removal in the file manager:

pip3 install nautilus-python --break-system-packages
cp /usr/share/nautilus-python/extensions/mat2_nautilus.py ~/.local/share/nautilus/extensions/

Restart Nautilus: nautilus -q && nautilus

Now right-click any file → Remove metadata.

Windows: ExifTool Context Menu

Add ExifTool to Windows right-click menu for easy access:

Create a file ExifTool_remove_metadata.reg:

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\*\shell\Remove Metadata]
@="Remove Metadata (ExifTool)"

[HKEY_CLASSES_ROOT\*\shell\Remove Metadata\command]
@=""C:\Windows\exiftool.exe" -all= -overwrite_original "%1""

Double-click to import. Now right-click any file → Remove Metadata.

PDF-Specific Cleaning

PDFs are notoriously metadata-rich. Beyond ExifTool, use qpdf for thorough PDF sanitization:

# Install
sudo apt install qpdf

# Linearize and strip metadata
qpdf --linearize input.pdf output.pdf

# Combined with ExifTool
exiftool -all= output.pdf

Verifying Removal

After cleaning, verify metadata is gone:

exiftool cleaned_photo.jpg
# Should show minimal output — file type, size, dimensions only

# Check for GPS specifically
exiftool -GPS:all cleaned_photo.jpg
# Should return nothing

Practical Privacy Workflow

Before posting photos online or sharing documents:

1. Copy files to a working directory
2. Run exiftool -all= -overwrite_original *.jpg *.png *.pdf
3. Verify with exiftool filename.jpg
4. Share the cleaned files

For sensitive documents, also use LibreOffice’s built-in metadata cleaner: File → Properties → Reset Properties, then re-save.

Metadata removal takes seconds and eliminates a significant privacy leakage vector that most people never consider.