Pingbacks-Trackbacks-Delete the old ones

I have disabled trackbacks and pingbacks in settings-discussions. But when I view a post on my site in edit and scroll down, there is a tab which let me to send trackbacks and it also shows “Already Pinged” Under this I see all the old selfpings. Many of them I already removed and many of them pointing to an old post which was removed. How can I get rid of this old selfpings?

Thank you very much for looking into this,
July