Does any one know if you can delete comments that people posted on your istructable?

No, you can't. You can flag them as inappropriate if they're spam, or mean-spirited, or contain objectionable words or obscenity, but flagging comments that you just disagree with will not win you any friends among Robot's minions.
kelseymh7 years ago
No.  RMS has the complete answer.  You can delete comments from your Orangeboard (in your profile), but that's all.
lemonie7 years ago
No, but you can FLAG them for deletion.