Following on from my comment on your question.

The solution would be to hook your own filter onto the same functions sanitize_title_with_dashes does, in this case i think you're just aiming to hook onto sanitize_title as is done with sanitize_title_with_dashes.

Simply ensure you hook on after sanitize_title_with_dashes, which is hooked on at the default priority of 10.

Eg.

add_filter('sanitize_title', 'limpiar_slug', 11 );

No need to hack core files.

EDIT BELOW:

You could give some regex a try, here's a sample you can play with, code adapted from Adriana Villafañe's code in response to Regular expression - any text to URL friendly one on StackOverflow.

add_filter( 'sanitize_title', 'sanitize_title_extra' );

function sanitize_title_extra( $title ) {

    $friendlyURL = htmlentities($title, ENT_COMPAT, "UTF-8", false); 
    $friendlyURL = preg_replace('/&([a-z]{1,2})(?:acute|lig|grave|ring|tilde|uml|cedil|caron);/i','\1',$friendlyURL);
    $friendlyURL = html_entity_decode($friendlyURL,ENT_COMPAT, "UTF-8"); 
    $friendlyURL = preg_replace('/[^a-z0-9-]+/i', '-', $friendlyURL);
    $friendlyURL = preg_replace('/-+/', '-', $friendlyURL);
    $friendlyURL = trim($friendlyURL, '-');
    $friendlyURL = strtolower($friendlyURL);
    return $friendlyURL;

}

Seems to do the trick of clearing up some unwanted characters, feel free to tweak, etc...

Following on from my comment on your question.

The solution would be to hook your own filter onto the same functions sanitize_title_with_dashes does, in this case i think you're just aiming to hook onto sanitize_title as is done with sanitize_title_with_dashes.

Simply ensure you hook on after sanitize_title_with_dashes, which is hooked on at the default priority of 10.

Eg.

add_filter('sanitize_title', 'limpiar_slug', 11 );

No need to hack core files.

EDIT BELOW:

You could give some regex a try, here's a sample you can play with, code adapted from Adriana Villafañe's code in response to Regular expression - any text to URL friendly one on StackOverflow.

add_filter( 'sanitize_title', 'sanitize_title_extra' );

function sanitize_title_extra( $title ) {

    $friendlyURL = htmlentities($title, ENT_COMPAT, "UTF-8", false); 
    $friendlyURL = preg_replace('/&([a-z]{1,2})(?:acute|lig|grave|ring|tilde|uml|cedil|caron);/i','\1',$friendlyURL);
    $friendlyURL = html_entity_decode($friendlyURL,ENT_COMPAT, "UTF-8"); 
    $friendlyURL = preg_replace('/[^a-z0-9-]+/i', '-', $friendlyURL);
    $friendlyURL = preg_replace('/-+/', '-', $friendlyURL);
    $friendlyURL = trim($friendlyURL, '-');
    $friendlyURL = strtolower($friendlyURL);
    return $friendlyURL;

}

Seems to do the trick of clearing up some unwanted characters, feel free to tweak, etc...

Following on from my comment on your question.

The solution would be to hook your own filter onto the same functions sanitize_title_with_dashes does, in this case i think you're just aiming to hook onto sanitize_title as is done with sanitize_title_with_dashes.

Simply ensure you hook on after sanitize_title_with_dashes, which is hooked on at the default priority of 10.

Eg.

add_filter('sanitize_title', 'limpiar_slug', 11 );

No need to hack core files.

Following on from my comment on your question.

The solution would be to hook your own filter onto the same functions sanitize_title_with_dashes does, in this case i think you're just aiming to hook onto sanitize_title as is done with sanitize_title_with_dashes.

Simply ensure you hook on after sanitize_title_with_dashes, which is hooked on at the default priority of 10.

Eg.

add_filter('sanitize_title', 'limpiar_slug', 11 );

No need to hack core files.

EDIT BELOW:

You could give some regex a try, here's a sample you can play with, code adapted from Adriana Villafañe's code in response to Regular expression - any text to URL friendly one on StackOverflow.

add_filter( 'sanitize_title', 'sanitize_title_extra' );

function sanitize_title_extra( $title ) {

    $friendlyURL = htmlentities($title, ENT_COMPAT, "UTF-8", false); 
    $friendlyURL = preg_replace('/&([a-z]{1,2})(?:acute|lig|grave|ring|tilde|uml|cedil|caron);/i','\1',$friendlyURL);
    $friendlyURL = html_entity_decode($friendlyURL,ENT_COMPAT, "UTF-8"); 
    $friendlyURL = preg_replace('/[^a-z0-9-]+/i', '-', $friendlyURL);
    $friendlyURL = preg_replace('/-+/', '-', $friendlyURL);
    $friendlyURL = trim($friendlyURL, '-');
    $friendlyURL = strtolower($friendlyURL);
    return $friendlyURL;

}

Seems to do the trick of clearing up some unwanted characters, feel free to tweak, etc...