Rather than emptying out the bug database, I prefer keeping two different "levels" of bug reports. There's the "current" bug database, which you try to keep small and which you clean regularly and work from. And there's the "deep backlog" which winds up being pretty much a collection of random junk. The "deep backlog" is rarely looked at (so it doesn't become a waste of time and attention), but you also don't throw it out wholesale, because it costs almost nothing to keep around. Occasionally you'll try to data-mine the deep backlog. You may also go through every year or two and do a mass cleanup; or you may allow a sort of "voting" process to identify items from the deep backlog that are worth considering for the "real" bug list.