Freeing up a formerly-used slug?

I’ve done a couple of create-delete cycles with a BuddyPress Group name (“Best Practices”) on a site I’m just setting up, and along the way I must have created something that’s sitting in the database using the slug “best-practices” — because when I now try to create the group, I get a message that the slug “best-practices” is unavailable, and the system has used “best-practices-[random_number]” instead.

I assume that if I can delete (and empty from Trash) the entry using that slug, I could use it again. I can’t find any current content using that slug (there’s hardly any content right now anyway), but I suppose it might be sitting in some Trash container someplace that I can’t find.

Suggestions on finding and deleting the offending item from the database?

Thanks.