When you no longer have use for a particular business rule and would it removed, you can do so in your Business Rules page.
Option 1) Delete a single rule
Locate the rule you'd like to delete, click on the vertical ellipses on the right side of the screen and select "Delete Rule."
Option 2) Bulk delete
When you need to delete more than one rule of the same type, hover over the icons to the left - you will see the icons change into checkboxes - and select the rules you'd like to delete. Once you're done selecting, click the trash icon at the top of the page to delete.
Note: You can also turn off the effects of a business rule by turning it off.