Add a button to remove watched videos from page

Remove-Watched-Button.user.js

// ==UserScript==
// @name         Remove Watched Button
// @namespace    http://nielk1.com/
// @version      1.0
// @description  Add a button to remove watched videos from page
// @author       You
// @match        https://www.youtube.com/feed/subscriptions
// @grant        none
// ==/UserScript==

// Best Used With https://chrome.google.com/webstore/detail/better-youtube-watch-hist/lleajdkalfbohpinoaekajagdefaeckd?utm_source=chrome-app-launcher-info-dialog

function addJQuery(callback) {
    var script = document.createElement("script");
    script.setAttribute("src", "//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js");
    script.addEventListener('load', function() {
        var script = document.createElement("script");
        script.textContent = "window.jQ=jQuery.noConflict(true);(" + callback.toString() + ")();";
        document.body.appendChild(script);
    }, false);
    document.body.appendChild(script);
}
function main(){
    jQ(document).ready(function() {
        jQ('.appbar-nav-menu').append('<li><a href="#" id="script_clear_watched_videos" class="yt-uix-button spf-link yt-uix-sessionlink yt-uix-button-epic-nav-item yt-uix-button-size-default" aria-selected="false"><span class="yt-uix-button-content">Clear Watched</span></a></li>');
        jQ('#script_clear_watched_videos').on('click',function(evt){
            evt.preventDefault();
            jQ('.yt-shelf-grid-item>.watched').each(function(idx,elem){jQ(elem).parent().remove();});
            jQ('.yt-shelf-grid-item>>>.watched').each(function(idx,elem){jQ(elem).parent().parent().parent().remove();});
        });
    });
}
// load jQuery and execute the main function
addJQuery(main);