diff --git a/boil_kettle/mqtt.ino b/boil_kettle/mqtt.ino
index 68a8bf1..66e94ba 100644
--- a/boil_kettle/mqtt.ino
+++ b/boil_kettle/mqtt.ino
@@ -46,6 +46,7 @@ void MessageReceived(char* topic, byte* payload, unsigned int length) {
     // Update PWM setpoint.
     setting = cJSON_GetObjectItemCaseSensitive(monitor_json, "setpoint");
     KettleDuty = setting->valueint;
+    cJSON_Delete(monitor_json);
   }
 }
 
@@ -70,5 +71,6 @@ static void SendSensorData() {
 
 
   mqtt_client.publish(topic, msg);
+  cJSON_Delete(monitor);
 
 }