Close comments: Automatically close comments on posts and pages.
Close pingbacks and trackbacks: Automatically close pingbacks and trackbacks on posts and pages.
Choose how old: Choose a custom time period as to when the comments, pingbacks and trackbacks need to be closed
Scheduling: You can also schedule a cron job to automatically close comments, pingbacks and trackbacks daily
Bonus: Delete post revisions
via WordPress › Auto-Close Comments, Pingbacks and Trackbacks « WordPress Plugins.
How do I close comment threads?
Closing a comment thread is used to halt the discussion while allowing the current comments to remain visible. Closing comments can be done several ways:
For your entire site you can specify how long you want comments to remain open after the thread has been created. You can find this option in your Disqus admin’s Settings > General page under Automatic Closing.
via How do I close comment threads? | DISQUS.
Automatically Closing Comments
It’s possible to turn comments off automatically after a certain number of days. To do that, go to the Settings -> Discussion page and look for Other comment settings on the left. Check the box next to the following option, fill in the number of days, and save.