If you no longer want a published transformation script to be available for use in other project data sets, you can un-publish the script. Un-publishing does not remove the script from projects in which it was previously loaded.
To un-publish a transformation script:
Go to the Catalog and locate the data set associated with the published script.
Open the details pane for the data set.
Select the Script tab.
Click the x icon to remove the script from the data set.