Click on the "Jobs" Tab and enter the job number in the search box if known. If not, you can search for the job address here, instead.
Click on the Job Number.
You will see all records linked to that job number.
Click on the flame icon to the right of the draft you wish to delete.
Scroll to the bottom of the page, click on "Delete".
Click "Yes" to confirm to complete the deletion.
Once you have deleted a draft you cannot get it back! This includes if you turn an already issued certificate back into a draft by pressing "Edit". So make sure to be careful when deleting your draft certificates and only do so if you are certain you will never need it again!