You can use your web developer tools in your browser to do that for you.
WARNING
This will delete your CSS and HTML customizations without warning!
NOT SAFE unless you don’t care about your customizations.
How To:
Make sure to be logged in as admin, open up the developer tools and paste the following code in it, then press [return]
$.ajax({url: '/admin/site_customizations/1', type: 'DELETE'});
$.ajax({url: '/admin/site_customizations/2', type: 'DELETE'});
$.ajax({url: '/admin/site_customizations/3', type: 'DELETE'});
$.ajax({url: '/admin/site_customizations/4', type: 'DELETE'});
$.ajax({url: '/admin/site_customizations/5', type: 'DELETE'});
$.ajax({url: '/admin/site_customizations/6', type: 'DELETE'});
$.ajax({url: '/admin/site_customizations/7', type: 'DELETE'});
$.ajax({url: '/admin/site_customizations/8', type: 'DELETE'});
$.ajax({url: '/admin/site_customizations/9', type: 'DELETE'});
$.ajax({url: '/admin/site_customizations/10', type: 'DELETE'});
$.ajax({url: '/admin/site_customizations/11', type: 'DELETE'});
Again, THIS IS NOT SAFE unless you don’t care about your customizations.
After this, just hit F5 and reload the page.
Good luck! 