diff --git a/esphomeyaml/__main__.py b/esphomeyaml/__main__.py
index e6c0d5ae32..8c814446ca 100644
--- a/esphomeyaml/__main__.py
+++ b/esphomeyaml/__main__.py
@@ -451,6 +451,8 @@ def parse_args(argv):
                            default=6052)
     dashboard.add_argument("--password", help="The optional password to require for all requests.",
                            type=str, default='')
+    dashboard.add_argument("--open-ui", help="Open the dashboard UI in a browser.",
+                           action='store_true')
 
     return parser.parse_args(argv[1:])
 
diff --git a/esphomeyaml/dashboard/dashboard.py b/esphomeyaml/dashboard/dashboard.py
index 4cec13496a..dfa079392b 100644
--- a/esphomeyaml/dashboard/dashboard.py
+++ b/esphomeyaml/dashboard/dashboard.py
@@ -117,6 +117,13 @@ class EsphomeyamlValidateHandler(EsphomeyamlCommandWebSocket):
         return ["esphomeyaml", config_file, "config"]
 
 
+class EsphomeyamlCleanMqttHandler(EsphomeyamlCommandWebSocket):
+    def build_command(self, message):
+        js = json.loads(message)
+        config_file = os.path.join(CONFIG_DIR, js['configuration'])
+        return ["esphomeyaml", config_file, "clean-mqtt"]
+
+
 class SerialPortRequestHandler(BaseHandler):
     def get(self):
         if not self.is_authenticated():
@@ -213,6 +220,7 @@ def make_app(debug=False):
         (r"/run", EsphomeyamlRunHandler),
         (r"/compile", EsphomeyamlCompileHandler),
         (r"/validate", EsphomeyamlValidateHandler),
+        (r"/clean-mqtt", EsphomeyamlCleanMqttHandler),
         (r"/download.bin", DownloadBinaryRequestHandler),
         (r"/serial-ports", SerialPortRequestHandler),
         (r"/wizard.html", WizardRequestHandler),
@@ -251,6 +259,12 @@ def start_web_server(args):
                  args.port, CONFIG_DIR)
     app = make_app(args.verbose)
     app.listen(args.port)
+
+    if args.open_ui:
+        import webbrowser
+
+        webbrowser.open('localhost:{}'.format(args.port))
+
     try:
         tornado.ioloop.IOLoop.current().start()
     except KeyboardInterrupt:
diff --git a/esphomeyaml/dashboard/templates/index.html b/esphomeyaml/dashboard/templates/index.html
index 9a0abdae0b..a13891f16f 100644
--- a/esphomeyaml/dashboard/templates/index.html
+++ b/esphomeyaml/dashboard/templates/index.html
@@ -159,6 +159,10 @@
       margin-right: 24px;
       width: 350px;
     }
+
+    .dropdown-trigger {
+      cursor: pointer;
+    }
   </style>
 
   <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
@@ -191,7 +195,7 @@
 
 <main>
 <div class="container">
-  {% for file, full_path in zip(files, full_path_files) %}
+  {% for i, (file, full_path) in enumerate(zip(files, full_path_files)) %}
   <div class="row">
     <div class="col s8 offset-s2 m10 offset-m1 l12">
       <div class="card horizontal">
@@ -200,7 +204,10 @@
         </div>
         <div class="card-stacked">
           <div class="card-content">
-            <span class="card-title">{{ escape(file) }}</span>
+            <span class="card-title">
+              {{ escape(file) }}
+              <i class="material-icons right dropdown-trigger" data-target="dropdown-{{ i }}">more_vert</i>
+            </span>
             <p>
               Full path: <code class="inlinecode">{{ escape(full_path) }}</code>
             </p>
@@ -211,6 +218,9 @@
             <a href="#" class="action-show-logs" data-node="{{ file }}">Show Logs</a>
             <a href="#" class="action-validate" data-node="{{ file }}">Validate</a>
           </div>
+          <ul id="dropdown-{{ i }}" class="dropdown-content">
+            <li><a href="#" class="action-clean-mqtt" data-node="{{ file }}">Clean MQTT</a></li>
+          </ul>
         </div>
       </div>
     </div>
@@ -462,6 +472,18 @@
   </div>
 </div>
 
+<div id="modal-clean-mqtt" class="modal modal-fixed-footer">
+  <div class="modal-content">
+    <h4>Clean MQTT discovery <code class="inlinecode filename"></code></h4>
+    <div class="log-container">
+      <pre class="log"></pre>
+    </div>
+  </div>
+  <div class="modal-footer">
+    <a class="modal-close waves-effect waves-green btn-flat stop-logs">Stop</a>
+  </div>
+</div>
+
 <a class="btn-floating btn-large ribbon-fab waves-effect waves-light pink accent-2" id="setup-wizard-start">
   <i class="material-icons">add</i>
 </a>
@@ -539,6 +561,7 @@
           if (allEqual)
             return;
         }
+        const hasNewPort = response.length >= ports.length;
 
         ports = response;
 
@@ -559,7 +582,7 @@
         }
 
         M.FormSelect.init(portSelect, {});
-        if (!begin)
+        if (!begin && hasNewPort)
           M.toast({html: "Discovered new serial port."});
       });
   };
@@ -784,6 +807,48 @@
     link.click();
   });
 
+  const cleanMqttModalElem = document.getElementById("modal-clean-mqtt");
+
+  document.querySelectorAll(".action-clean-mqtt").forEach((btn) => {
+    btn.addEventListener('click', (e) => {
+      configuration = e.target.getAttribute('data-node');
+      const modalInstance = M.Modal.getInstance(cleanMqttModalElem);
+      const log = cleanMqttModalElem.querySelector(".log");
+      log.innerHTML = "";
+      const stopLogsButton = cleanMqttModalElem.querySelector(".stop-logs");
+      let stopped = false;
+      stopLogsButton.innerHTML = "Stop";
+      modalInstance.open();
+
+      const filenameField = cleanMqttModalElem.querySelector('.filename');
+      filenameField.innerHTML = configuration;
+
+      const logSocket = new WebSocket(wsUrl + "/clean-mqtt");
+      logSocket.addEventListener('message', (event) => {
+        const data = JSON.parse(event.data);
+        if (data.event === "line") {
+          const msg = data.data;
+          log.innerHTML += colorReplace(msg);
+        } else if (data.event === "exit") {
+          stopLogsButton.innerHTML = "Close";
+          stopped = true;
+        }
+      });
+      logSocket.addEventListener('open', () => {
+        const msg = JSON.stringify({configuration: configuration});
+        logSocket.send(msg);
+      });
+      logSocket.addEventListener('close', () => {
+        if (!stopped) {
+          M.toast({html: 'Terminated process.'});
+        }
+      });
+      modalInstance.options.onCloseStart = () => {
+        logSocket.close();
+      };
+    });
+  });
+
   const modalSetupElem = document.getElementById("modal-wizard");
   const setupWizardStart = document.getElementById('setup-wizard-start');
   const startWizard = () => {
diff --git a/esphomeyaml/mqtt.py b/esphomeyaml/mqtt.py
index ca60800a6c..0160d51197 100644
--- a/esphomeyaml/mqtt.py
+++ b/esphomeyaml/mqtt.py
@@ -83,7 +83,9 @@ def clear_topic(config, topic, username=None, password=None, client_id=None):
         discovery_prefix = config[CONF_MQTT].get(CONF_DISCOVERY_PREFIX, u'homeassistant')
         name = config[CONF_ESPHOMEYAML][CONF_NAME]
         topic = u'{}/+/{}/#'.format(discovery_prefix, name)
-    _LOGGER.info(u"Clearing messages from %s", topic)
+    _LOGGER.info(u"Clearing messages from '%s'", topic)
+    _LOGGER.info(u"Please close this window when no more messages appear and the "
+                 u"MQTT topic has been cleared of retained messages.")
 
     def on_message(client, userdata, msg):
         if not msg.payload or not msg.retain: