Richie Lee shows how to remove Analysis Services cube partitions using Powershell:
One such an example of ad-hoc DBA tasks was when I had to delete about 600 partitions from a measure group that had thousands of partitions. Doing this manually would be ridiculous, so at the time I created a SQL script that used some dynamic T-SQL to create the delete commands in XMLA. XMLA has no “delete if exist” type syntax, so if I needed to run this again, this dynamic SQL output wouldn’t work. And so I decided that if I had to run the same task a gain I would write a PowerShell script that would run DSC-style and drop the partitions that were no longer required. And funnily enough, that is exactly what I had to do.
I knew I would be able to create a Powershell script that used AMO to check if a partition exists and drop it if it did. I also wanted the script to take into account any other partitions in other measure groups that may also need to be dropped. So I made sure the script uses PowerShell switches that can be included when calling the function, and if they are included then the pertaining partitions in that measure group will be deleted. So you can run the script for one, some or all of the measure groups in a cube.
Click through for the script.