can Display Lists be deleted?

Can I create many Display Lists run-time?
Actually I need just a few DL, but I need to update them.

When I create a new list indexed with a number of a previously created list, is the DL overwrited? Or is there a function to destroy the list?
Does it free the alloced memory??

When you overwrite a displaylist, the old one is automatically deleted and replaced with the new one.

If you want to delete it yourself, you can use glDeleteLists();