diff --git a/hbd/server/http.py b/hbd/server/http.py
index 4ce5070..c40e3fe 100644
--- a/hbd/server/http.py
+++ b/hbd/server/http.py
@@ -537,6 +537,7 @@ async def start(
                 hosts_with_plugins.append({
                     "name": hostname,
                     "plugins": list(host.plugin_data.keys()),
+                    "is_owner": _can_own_host(current_user, host),
                 })
 
         tmpl = env.get_template("plugins.html")
diff --git a/hbd/server/main.py b/hbd/server/main.py
index 2c62688..95701bd 100644
--- a/hbd/server/main.py
+++ b/hbd/server/main.py
@@ -101,9 +101,10 @@ async def reload_configuration(config_obj, config_path, components):
             access = config_mod.get_host_access(new_config, hostname)
             host.apply_access(access["owner"], access["managers"], access["monitors"])
 
-        # Reload threshold checker
+        # Reload threshold checker and prune alerts orphaned by the new config
         if 'threshold_checker' in components:
             components['threshold_checker'].reload(new_config)
+            components['threshold_checker'].purge_stale_alerts(hbdclass)
         
         # Note: Changes to the following require restart:
         # - hb_port, hbd_port, ws_port (already bound)
@@ -241,6 +242,10 @@ async def _run_async(config, config_path=None):
     )
     udp.restore_connection_timers(hbdclass, restore_ctx)
 
+    # Drop alert states that no longer have a matching threshold (stale after
+    # upgrade or config change between runs).
+    threshold_checker.purge_stale_alerts(hbdclass)
+
     # HTTP server (asyncio-based via aiohttp)
     try:
         http_task = asyncio.create_task(
diff --git a/hbd/server/templates/plugins.html b/hbd/server/templates/plugins.html
index 41f1ff2..a74de89 100644
--- a/hbd/server/templates/plugins.html
+++ b/hbd/server/templates/plugins.html
@@ -131,6 +131,27 @@
       text-overflow: ellipsis;
     }
 
+    .host-action-btn {
+      font-size: 0.75em;
+      font-weight: bold;
+      padding: 3px 10px;
+      border-radius: 4px;
+      border: none;
+      cursor: pointer;
+      text-decoration: none;
+      white-space: nowrap;
+    }
+    .host-action-btn.update-btn {
+      background: #e3f2fd;
+      color: #1565c0;
+    }
+    .host-action-btn.update-btn:hover { background: #bbdefb; }
+    .host-action-btn.delete-btn {
+      background: #ffebee;
+      color: #c62828;
+    }
+    .host-action-btn.delete-btn:hover { background: #ffcdd2; }
+
     /* ── Host body ──────────────────────────────────────────────── */
 
     .host-body {
@@ -379,6 +400,14 @@
               <span class="nagios-badge" id="nagios-badge-{{ host.name }}">—</span>
               {% endif %}
               <span class="os-label" id="os-label-{{ host.name }}"></span>
+              {% if host.is_owner %}
+              <a class="host-action-btn update-btn"
+                 href="/u?h={{ host.name }}"
+                 onclick="event.stopPropagation()">Update</a>
+              <a class="host-action-btn delete-btn"
+                 href="/d?h={{ host.name }}"
+                 onclick="event.stopPropagation(); return confirm('Delete host {{ host.name }}?')">Delete</a>
+              {% endif %}
             </div>
           </div>
 
diff --git a/hbd/server/threshold.py b/hbd/server/threshold.py
index fa4f5a1..9d86a00 100644
--- a/hbd/server/threshold.py
+++ b/hbd/server/threshold.py
@@ -1276,6 +1276,26 @@ class ThresholdChecker:
             alert_state.last_notification = now
             alert_state.notification_count += 1
     
+    def purge_stale_alerts(self, hbdclass) -> None:
+        """Remove alert states that have no matching threshold configuration.
+
+        Called after startup (pickle restore) and after each config reload so
+        that alerts orphaned by configuration changes do not linger forever.
+        Alerts whose metric_path is not present in the current threshold config
+        for that host are silently dropped.
+        """
+        for hostname, host in hbdclass.Host.hosts.items():
+            if not host.alert_states:
+                continue
+            configured = self.get_thresholds_for_host(hostname)
+            stale = [mp for mp in host.alert_states if mp not in configured]
+            for mp in stale:
+                logger.info(
+                    "Purging stale alert state for %s / %s (no threshold configured)",
+                    hostname, mp,
+                )
+                del host.alert_states[mp]
+
     def get_active_alerts(self, alert_states: Dict[str, AlertState]) -> list:
         """
         Get all currently active (non-OK) alerts.