How to really flush the various nscd caches

Since I keep finding posts that tell you to restart nscd to flush its caches, I'll tell you how to really do it.

The nscd caches are saved to disk, On my Fedora system, they are located in /var/db/nscd:

[root@dev402 ~]# ls /var/db/nscd/
group hosts netgroup passwd services

When you stop nscd, these files will just stay there, so restarting really doesn't flush your nscd caches.
What you need to do is use the --invalidate option, e.g.:

nscd --invalidate=hosts