Hi,
You can enter your infoobject in RSDMD t-code. It will take you to maintain master data screen-->Press Execute-->Select the unwanted record-->Click on pencil button and edit it-->Save it on top-->Come out of the t-code and run Attribute Change run. Then, your reports will not show this data.
Sometimes, after deleting from RSDMD, the deleted record will be again visible in RSDMD due to SID numbers still available in the system. That means, the record has not been genuinely deleted. In this case, as i told you in my first reply, go to SE14 and delete the data from the database.
Regards,
Suman