Originally Posted by OGdroidster
Sometimes that does not not work but if it works for you more power to you. Plus it makes no sense to keep something around that's not being used.
A dirty flash means not wiping System partition. I have seen a lot of people who wipe more than they should during a dirty fl;ash. If the ROM ZIP is a properly working standard standard custom ROM, it works.
As for "keeping something around that's not being used", when the dirty flash works as it is designed, it means not having to uninstall the APK every time a new version of the ROM is released and flashed. It stays frozen/hidden.