Many software packages in Ubuntu come along with a package configuration file. These files are used to control various settings for their particular package. In most cases, there is no reason to keep these files around after you've removed a package from you system. They get removed from your system along with the software package if you happen to use the apt-get purge command or if you mark it for "Complete Removal" in Synaptic. But what if you didn't do that when you removed the package?
One thing you can do is reinstall the package and then purge it from your system, but there's got to be a better way. Well, it turns out that you can use the dpkg command to do the job. You actually use dpkg twice: once to find the orphaned configuration files, and again to actually remove the files. The following command has been tested on Ubuntu 10.04 and 10.10, but it should work on any Debian or Ubuntu based Linux distribution.