example drush sanitize hook

webform.drush.inc

<?php

function paranoia_drush_sql_sync_sanitize($source) {
  drush_sql_register_post_sync_op('webform_delete_webform_submissions',
    dt('Delete all webform_submission primary entries'),
    "delete from webform_submissions;");
  drush_sql_register_post_sync_op('webform_delete_webform_submitted_data',
    dt('Delete all webform_submitted_data field level entries'),
    "delete from webform_submitted_data;");
}