Index: src/wp-includes/class-wp-editor.php
===================================================================
--- src/wp-includes/class-wp-editor.php	(revision 29015)
+++ src/wp-includes/class-wp-editor.php	(working copy)
@@ -476,7 +476,32 @@
 							{selector: 'p,h1,h2,h3,h4,h5,h6,td,th,div,ul,ol,li', styles: {textAlign:'right'}},
 							{selector: 'img,table,dl.wp-caption', classes: 'alignright'}
 						],
-						strikethrough: {inline: 'del'}
+						strikethrough: {inline: 'del'},
+						removeformat: [
+							{
+								selector: 'b,strong,em,i,font,u,strike,sub,sup,dfn,code,samp,kbd,var,cite,mark,q',
+								remove: 'all',
+								split: true,
+								expand: false,
+								block_expand: true,
+								deep: true
+							},
+							{
+								selector: 'span',
+								attributes: ['style', 'class'],
+								remove: 'empty',
+								split: true,
+								expand: false,
+								deep: true
+							},
+							{
+								selector: '*',
+								attributes: ['style'],
+								split: false,
+								expand: false,
+								deep: true
+							}
+						]
 					}",
 					'relative_urls' => false,
 					'remove_script_host' => false,