Identifying and deleting unused DNS entries

[blrmaani]

I maintain a DNS server running BIND 9.2.x. We have several unused
entries
but I donot want to delete it before making sure that these A records/
CNAMES
are not being queried.

One approach I know of is to enable querylog, check for the names to
be deleted in the querylog and delete it if these names are NOT in the
querylog.

Does BIND maintain some kind of statistics per CNAME/A record ?
Is there any better approach to solve this problem?

Thanks in advance
Blr.