Usually you do absolutely nothing. Since the ability to comment was introduced, comments have been considered 2nd class citizens, and have no edit history at all (so you can't see what was changed and when and by whom).  

There is virtually no capability to edit comments for regular users, the only exception being the original author of the comment can edit it at will for 5 minutes after it was posted.  You cannot edit anyone else's comment ever, regardless of reputation.

Moderators can edit comments, but this not a common practice and usually only done for serious issues (such as a useful comment that is very rude or offensive).  Small typos or grammar mistakes are often not changed, simply because it would be a full time job for a moderator to worry about cleaning things up.

The best thing to do if you encounter a typo in a comment that potentially can cause confusion is to leave your own comment and ask "@bobLoblaw do you mean .....?".

For the kinds of typos, I'm thinking of things such as:


Forgetting a "not" or other typo/omission that causes the comment to say something other than what you think it was intended to mean
A serious spelling mistake that changes the meaning of a post 
A significant typo in a code snippet that would have a different result than what is being intended.


Minor stuff like a missing "s" or a using its instead of it's should just be left alone.

Don't flag a comment for moderator attention to correct a typo unless the issue is so serious that it needs to be fixed.  Moderators have enough flags to handle, so they don't need a whole host of new ones asking them to capitalize "i" in thousands of comments.

What should I do with comments that need to be edited?
Will I lose my statue? Will I lose my Hall of Monuments point progression? Or is it safe? What happens if I destroy a minipet dedicated at the Hall of Monuments?
