Problem revoking all privileges

I'm using MySQL 4.1 (I think... a late 4 anyway) on a Gentoo box.  It's only a semi-live situation and no need for security just yet.

After messing with privileges a bit, I decided to revoke whatever privileges are already applied and specifically grant only the ones I need (using a shell script).  To revoke, the obvious choice was to use (if I can remember it correctly):

mysql> revoke ALL on *.* from '%'

However, I'm getting an error about that privilege not applied, and I've read it's because ALL isn't an alias for all privileges, it's a privilege in itself.  I think this is the reason I can't remove it!  So, the question is, how can I revoke all the permissions that have been applied to a database (recursing into table/columns etc.) ?

Many thanks,
Steve :)