This document is close to what you are looking for: How to: Delete patches from target machines using a Custom Action
The only changes needed are in the Custom Actions tab in the Deployment Template..
To remove the Scheduler:
To remove the contents of the ProPatches folder: (It cannot remove the logs or the installation folder for the Customer Action deployment)
if exist "%PathtoFixes%..\..\..\ProPatches" (RD /Q /S "%PathtoFixes%..\..\..\ProPatches")
It will look like this: (order is important)
This will uninstall the Shavlik Scheduler, remove all of the files and folders from the ProPatches folder excluding the Log and Installation folder.
Please test this before using on all of your targets.