###Close them as Too Localized
This question is unlikely to ever help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet.
If there is any suspicion that it might be user or bug related, or sometimes users make questions involving errors that cannot be reproduced anymore and since none of the answers can be verified as possible solutions these questions can be closed.
I then use this pro-forma comment
This question seems abandoned, the reported faults could be bug related, no longer valid on current versions of packages or cannot be solved without further confirmation from the OP. I am flagging this to be closed by a moderator. If you think this issue is still affecting you you can flag a moderator to re-open it.
Then I vote and flag to a moderator.
###Close them as Not a Real Question
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form.
If there is obviously not enough information in them, if comment requests were not met or is the user simply does not exist anymore.
I then normally use this pro-forma comment
This question seems abandoned, there is not further information or activity added to it for several months. I am flagging this to be closed by a moderator. If you think this issue is still affecting you you can flag a moderator to re-open it.
Then I vote and flag to a moderator.
Important to remember is that this is not a hunt to close old questions, this is a hunt to identify and possibly close questions that cannot be answered.
- If a question is less than 6 months old I would say not to touch it, hunt something else
Normally if is less than 6 months old, do not flag that or comment as abandoned. Vote to close and follow the normal procedure of the site, 5 votes and its closed if there is reason to do so. Remember, abandoned flags are exceptions to the rule! There is plenty of other questions that deserve the title of abandoned out there.
- If a question has solutions that you can edit, fix, sound reasonably true and are easily tested
Its important that if the answers to a question that seems abandoned sound good those can be considered helpful, if its obvious that a answer would satisfy the question then don't flag as abandoned. If the answers need some editing, do so. If you know the answer to a question that seems abandoned answer it!
- Read the questions and think about the consequences of flagging
I have seem many questions on the site that where old, about bugs or simply old bad questions with a comment as "do you think this issue still affects you?" yet they where left open after that comment for several months. Do not do this!
Take responsibility for every comment you drop on a question if your intention is to close it. Mark them down, add them to the favorites, track them down, just don't abandon a abandoned question!
I have found on the total opposite of the previous point some questions on the site with less then 3 months old where one of us flagged as abandoned and closed when they sounded perfectly good questions.
This should be avoided, there is so much on the site that can be closed why would we focus on closing these as abandoned? Again, don't close questions with less than 6 months as abandoned! If you think they will fit any of the closing options vote and leave them.