Print on paper. Physically cut out the pieces you want to send to remove. Scan.

Still suspect that someone can undo this from data may have been accidentally steaganographed across non-deleted parts of the image.

I think even after printing and scanning there could still be jpg artfacts from the original (e.g. if you scan lossless).

However, I wonder whether heavily compressing the redacted image would help remove any unwanted artefacts. But the best solution is probably to render the original file from scratch, without compression, before redacting the image.

Microdots may leak your identity this way (though I guess a really high resolution scan is needed for that)

Not sure but that might actually add your printer's unique dots to the scanned image.

https://en.wikipedia.org/wiki/Printer_tracking_dots