Removing Inactive Coupons in Order Management System
How do I delete coupons from the Order Management System?
Only unused coupons can be deleted. This can be done in bulk using the cleanup feature, or one at a time by clicking the delete button in the lower left of the coupon detail screen. (Get to the coupon detail screen by clicking the name of the coupon in the coupon list screen.)
If a coupon has been used, then you can deactivate it by adding an end date in the past, but you cannot delete the coupon from the system.