Hey come on guy's, kiss and make up! Whilst I suspect that Dodgers statement that "You can't delete anything with a pose file." is true for figures, and in deed for almost everything else, I'd just like to point out that there is at least one exception:

                targetGeom RoundFace
                        {
                        indexes 0
                                {
                                }
                        }

This will delete all the deltas from the targetGeom channel. Of coures this is only because Poser provides a specific mechanisam to do so, "indexes 0".