I'm not sure how effective it is with older notes, but twice I have been able to withdraw notes immediately after posting them when I saw a glaring mistake. 

Everything online is practically permanent so I'm developing a more consistent proof reading practice 🙂 

 "replace" is function is the way here. 

replace your note by a black hole img like this




https://image.nostr.build/04d0d3b80be2717ec461c11166adf2eebea14b0611fd1425af826f2508418b21.jpg


addendum: some say they can see black holes