Currently, in the Firefox product, we have roughly 540 bugs that are ready for closure. These are bugs that have not had any activity from their reporter for sometime, and have been marked as closeme by Triage. While each triage member has slightly different processes for closing old bugs, my process is usually as follows:

1. After a bug has been unattended for a significant amount of time (2 months or more), and at least one effort by a triage member has been made to request more information from the reporter, I will place a simple comment asking the reporter to test with the latest version of Firefox in a fresh profile. I will also place the following text in the bug’s whiteboard: “[CLOSEME YYYY-MM-DD]”, with the date set roughly 3-4 weeks into the future. If the reporter responds and begins providing needed information, than the CLOSEME tag is removed.
2. If no response comes from the reporter within the time specified, then I revisit my query of bugs ready for closure. I will post a comment stating that because there has been no reply, the bug will be closed as INCOMPLETE. I also try to make clear the fact that if the reporter continues to the see the issue in the latest version of Firefox and a fresh profile, they should comment so, and the bug can be reopened.