[Moru]

If you print to paper and scan you are mostly safe, but if you do a software print to a pdf document you might use a tool that saves the actual content as invisible text or the whole word document as an attachment to the pdf. I would print and scan physically if it was something important. Or just edit the word document to remove the stuff and then print and scan to avoid saving the edit history since I don't know if that will be saved somewhere.

Usually I'm in full control of the software myself so I just output X instead of the secret data.

[MaxBarraclough]

> I would print and scan physically

This degrades quality and wastes paper and toner. There are software tools to convert PDF to raster graphics.