Noticeboards can be explicitly lost (unmapped). Often you will not need to worry about this and will be happy to allow them to be unmapped on image exit. Sometimes, however, you may require explicit control. Note though that a noticeboard is not actually deleted until the last process unmaps it.
Find a noticeboard and an item within it.
NBS_FIND_NOTICEBOARD (`AUTOFIB', ! Noticeboard name TOPID,STATUS) ! Top-level ID NBS_FIND_ITEM (TOPID,`CURRENT_CONFIG',CONID,STATUS)
Lose the item and the noticeboard.
NBS_LOSE_ITEM (CONID,`CHECK',STATUS) NBS_LOSE_NOTICEBOARD (TOPID,`CHECK',STATUS)
Alternatively, if you like living dangerously, try this.
NBS_LOSE_NOTICEBOARD (TOPID,`FORCE',STATUS)
NBS The Noticeboard System