fully cleanse, yeah, but you can delete an awful lot.I believe it's virtually impossible to cleanse your digital footprint
If (like on here), someone has screenshotted or quoted your post, then it’s tough.
But you can clean up a lot.
I remember telling my (not young now) kids, that they should be aware that anything they write or post on any device is likely to be there for ever, so just make sure you never write something you might regret