GConf Cleaner can be a useful tool to get rid of unnecessary or invalid keys in the GConf database. This tool scans the GConf database for unlinked or invalid keys or keys which are no longer in use. The user can backup the files which will be deleted and restore them later if needed.
GConf Cleaner is available in Synaptic, go to System > Administration > Synaptic Package Manager. Click the Search button and type in gconf-cleaner. Once this application is found, right-click on the package name and select Mark for installation and then click on Apply. After the installation is completed GConf Cleaner can be found under Applications> System Tools> GConf Cleaner.
Keep in mind to create a backup before removing any invalid/unused/unknown GConf keys!
Backup files are always stored with the extension .reg.
Restoring a backup file
If there are some applications that no longer work properly after cleaning the GConf database, then the last backup should be restored. The following shows how to restore a backup:
Where <path_filename> is typed, the path and name of the intended backup file should be written.
More info about GConf Cleaner can be found here: http://code.google.com/p/gconf-cleaner/.