I cannot find a way to delete picklist values via the metadata API. I have read a lot from the Salesforce Metadata API docs, but it doesn't say wither or not you can do this.
I'm using version 39.0 of the API, which did add quite a bit of functionality to the metadata API, but nowhere does it mention how to update/replace/delete existing picklist values, rather focusing on creating metedata instead. Fields etc. I can delete, but picklist values seems to have an information black hole.
Does anyone know if this is possible? Any help would be greatly appreciated.