In poser 8? Jeez, IIRC you can delete them in the hierarchy editor if you have show all parameters checked. Locate and double click selected. In 11 it's an option in the parameters options drop down also if you have the morph dial selected. I don't have 8 installed so I can't be certain.

Or you can use this, which I still use for getting rid of extraneous empty dials generated by spawn operations. It works in windows 10 so I imagine it works in earlier versions, it's an external standalone...

Morph Manager

https://web.archive.org/web/20190812005225/http://www.morphography.uk.vu/dlutility.html

Or you can use Dimension3D's Binary Morph Editor, which is pretty useful for all sorts of things. It's a product here.