DELETE https://api.thingspeak.com/channels/4/feeds.json
       api_key = XXXXXXXXXXXXXXXX

HttpURLConnection urlConnection = null;
        try {
        URL url = new URL("http://api.thingspeak.com/channels/143467/feed.json?key=ADSJKFXMKVVJR32");
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("DELETE");
            urlConnection.connect();