WordPress post data cleanup. Very basic.

wordpress-cleanup-basic.php

<?php
/**
 * Example of using wp_kses() to clean up WordPress post data.
 */ 
function __cleanup_post_data(){
  global $wpdb;

  // default wordpress "allowed html" for posts
  $allowed_tags = wp_kses_allowed_html( 'post' );

  // posts
  $posts = $wpdb->get_results('SELECT ID,post_content,post_excerpt FROM wp_posts WHERE post_content like "%style%" OR post_excerpt like "%style%"');

  foreach( $posts as $i =>  $post ){
    // clean content
    $post->post_content = wp_kses( $post->post_content, $allowed_tags );

    // clean excerpt
    $post->post_excerpt = wp_kses( $post->post_excerpt, $allowed_tags );

    // update row in the db with new values
    $update_sql = $wpdb->prepare("UPDATE {$wpdb->posts} SET post_content = %s, post_excerpt = %s WHERE ID = %d",
      $post->post_content,
      $post->post_excerpt,
      $post->ID );

    $wpdb->query( $update_sql );
  }
}