The safest thing is to retype it. But that doesn’t cover the risk of synonym/frequency fingerprinting discussed elsewhere in this thread.
Plenty of discussions in this thread show why. Anonymous screenshot or picture? Image watermarks -> anything from subtle color changes, to sans/serif font changes, to word replacement. Anonymous text or summary? Word replacement, letter biasing encoding, etc. Anonymous audio? Inaudible frequencies, audible waveform deformation encoding, etc.
Nothing's out of the realm of possibility for the paranoid.
[0] I never bothered looking up where this came from until just now... interestingly it's from the IRA, and used in the total opposite way most people use it now... https://en.wikipedia.org/wiki/Brighton_hotel_bombing