On edit page click ‘Delete’ link.
Please note if you are trying to delete CU3ER that is already embedded in you page or post you will need to remove CU3ER from that pages in the first place. Also, wpCU3ER will not notify you about embedded CU3ERs if you have added CU3ER as template tag.
NOTE: Be careful when deleting CU3ER and make sure you have removed selected CU3ER from all pages/posts before deleting especially if you embedded CU3ER via template tag.
NOTE: All records from database will be deleted thus revert changes would not be possible.