You can easily delete the Commands on your site.
In the XNAT UI, select Administer → Plugin Settings
On the Plugin Settings page, choose Images & Commands. This screen is organized by docker image, with a table under each image listing the Commands that use that image.
Find the row for the Command you wish to delete. Click the button with a trash can icon in the Actions column to delete it.
A Confirmation dialog will appear. Click OK to delete the Command, or click Cancel or the X button in the corner to not delete the Command.