How to remove metadata from LibreOffice and RTF files

1 What a LibreOffice file keeps

• Properties: who made it and who saved it last, when, how many times and for how long it was edited, its template, and any custom fields.
• The program and the system: the version of LibreOffice, and the operating system it ran on.
• Printing: who printed it last and when, and the printer's name, which often names the office.
• A thumbnail: a picture of the first page, which file managers show as a preview.
• Tracked changes, with the text each deletion took out, and comments, with the name of whoever wrote each one.
• Photos placed in it, each with its own EXIF: where it was taken, with which camera.

The sample lease names the printer on the office's second floor, and keeps a deleted line that still says “The landlord accepts 18 000 UAH; offer that first.”

2 Remove it

Open the file in hexscope. It reads LibreOffice's text documents (.odt), spreadsheets (.ods) and presentations (.odp). Under What this document reveals, press Remove it — save a clean copy. In the copy:

• the properties, and the settings that name the printer, are emptied;
• the thumbnail becomes a blank picture, so the file still opens everywhere;
• tracked changes are accepted — what was deleted goes, with its text — and comments are deleted with their authors;
• photos lose their EXIF.

Then press Open the clean copy, and hexscope says what is gone.

3 RTF files

An RTF file — what WordPad, TextEdit and many older programs save — keeps the same kind of facts in plain text: the author and who saved it last, the company, when it was created, revised and printed, the program and its template, custom properties, and who made each tracked change. Its clean copy leaves them out, accepts tracked deletions and removes comments. A deletion that shares its group with other text stays, and hexscope says so.

4 In LibreOffice itself

• Personal information: Tools → Options → LibreOffice → Security → Options, turn on Remove personal information on saving, then save the file again.
• Properties: File → Properties → General, turn off Apply user data and press Reset Properties.
• Tracked changes: Edit → Track Changes → Accept All.
• Comments: right-click a comment and choose Delete All Comments.

Each works on the file open in LibreOffice, one at a time. Check the result either way: open the saved file in hexscope and see what is left.

5 Many files at once

Drop a folder on the page, or choose several files, and Save clean copies saves the clean ones as one ZIP, and on your own computer the command line tool does the same:

hexscope clean --verify --out clean/ documents/

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