"Information to be withheld should be black highlighted using a tool such as the word highlighter tool like this ⬛⬛⬛⬛⬛ and then printed off. This print out should then be scanned in and saved as a PDF."
...shred cut out parts, burn remains, mix with water, encase in cement, explode, divide rubble into four parts, disperse one part each in Lake Superior, Pacific Ocean, Atlantic Ocean, and the Great Salt Lake; assume an alias, move to Alaska...
This is how military redactions have been done forever. If a soldier writes home to his family and includes classified details (“I watched the sun rise over Mt Vesuvius yesterday but today we are moving west”) the censors just cut out the text with a knife.
Firstly because it's a nice mix of analog and digital, and secondly because it's short enough to fit in a tweet - yet extremely secure.