Hello,   I would refer you to the OMEnt manual, but would need to know the version that you are running to do so. I have the link to version 3.6 below. Page 51 lists how to delete a discovery job.   [URL]
It looks like after an OME upgrade (maybe a reboot is enough, not sure) every discovery job is run again. How will it be possible to delete those? Those hosts from 2019 don't even exist anymore... [IMAGE]  
Very old discovery jobs are run again after upgrade