Remove Hidden Data

What is hidden data in a PDF?

Everything a reader does not see on the page but the file still carries: the author and title fields, an XMP metadata block, files attached inside the PDF, scripts that run when it opens or when a field changes, comments and highlights, and the small preview images and app data some programs leave behind. This tool lists each kind and removes the ones you tick.

What does it remove, exactly?

Document properties: every standard and custom key in the Info dictionary, and the XMP metadata block. Attached files: embedded files and file attachments. Scripts: document JavaScript, an opening script, additional actions on pages and fields. Comments and markup: notes, highlights, underlines, shapes, stamps and text boxes, with their popups. Thumbnails and app data: page preview images and private application data. Form answers: the typed values and the appearances that drew them, with the fields kept so they can still be filled in. Form answers are unticked by default, since clearing them is a choice. Removed content is not left in the file, not even unlinked: it is deleted and the file is rewritten without it.

What does it leave alone?

Links, optional-content layers and digital signatures are listed but never changed. Removing a link would break navigation, and removing a digital signature would invalidate it. The visible page content is never touched.

Will removing scripts break a form?

It can. Scripts often calculate totals, format dates or show and hide fields, and those stop working once removed. Fields stay fillable by hand. If you need the form's calculations, leave the scripts ticked off and keep the original.

Does it find text hidden under images or in white ink?

No. It removes structures the file declares as hidden data, not content drawn on the page. Text hidden by colour, text under an image, content outside the visible crop, and anything inside a picture are part of the page and stay. To remove content from the page itself, use the Redact tool.

Is this the same as the metadata tool?

It goes further. The metadata tool shows and clears the author, title and related fields, and the XMP block. This tool also removes attachments, scripts, comments and thumbnails, and lists what it leaves alone. It is not a full sanitiser: anything it does not list stays in the file.

Are my files uploaded?

No. The PDF is read and rewritten inside your browser, and the cleaned copy is downloaded from there. Nothing is sent to a server.