How do I clear a cached GPG passphrase from gnome-keyring-daemon?

How do I clear a cached GPG passphrase from gnome-keyring-daemon?

I searched around, and the best I could come up with was this:

$ pkill -HUP gnome-keyring-daemon

However, that had no effect whatsoever.  It's still caching my
passphrase.  I could kill the daemon entirely, and that certainly did
the trick, but I had to log out and back in to restart the daemon.

Here's a summary:

$ gpg -d msg.asc
(Gnome agent asks for passphrase the first time.  Good.)
Hello there.
Meet at dawn.

$ gpg -d msg.asc
(This time it doesn't ask for my passphrase.  Good!)
Hello there.
Meet at dawn.

# Now let's try deleting the cached passphrase:
$ pkill -HUP gnome-keyring-daemon

# See if it worked:
$ gpg -d msg.asc
(It did not ask for my passphrase.  BAD Gnome, BAD!!!)
Hello there.
Meet at dawn.


-- Patrick