How to Delete a Comment

The Help feature explaining how to delete a comment is at http://help.blogger.com/bin/answer.py?answer=1081&topic=23

Step 1. Log in to your blog account.
Step 2. Go to the blog with the comment (either to your own blog where someone else wrote a comment or to any blog where you left a comment.)
Step 3. Find the comment.
Step 4. Click on the trash icon at the end of the comment. (I had to use a magnifying glass to see it.)
Step 5. On the confirmation page, click on "Delete Comment".
Step 6. If you want to remove any trace that the comment was ever there, also check the "Remove Forever" option.
If you don't check this option, a message saying "This comment has been removed" will replace the comment. I find that seeing this message always makes me imagine all sorts of things that the author of the comment might have written that would appall decent people.

This reminds me of one of my favorite jokes.
A psychiatrist was giving a Rohrshach (sp?) test (the test where he shows ink blot images to a patient) and the patient saw a dirty picture in every ink blot. At the end of the session, the doctor said, "My gosh, you have a dirty mind." The patient replied, "Me? They're your dirty pictures!"

It is not possible to edit comments.
If you want to edit your own comment, you can simply delete it (use Ctrl/C to copy the original first) and then re-enter it (use Ctrl/V to paste in the original) and make the changes. (However, the timestamp will be modified to reflect the time of the new comment.)